Net Zero Homes: Why it's easy to build one now!

well welcome thanks for for being here today and I've spoken on net zero energy homes for several years now it's kind of feeling like you know we just ought to be doing this I mean we shouldn't need anybody speaking about it anymore because it should just be what we do I got my Tesla on Saturday and if you're not driving an electric vehicle I mean it's just it's where we're going in the future and and really the future is now I realize they're still a little on the spendy side it's more than I've ever spent on a car but I kind of feel the same way about about net zero energy homes net zero energy buildings it's just we can do it we have the technology it's not that hard it doesn't cost that much more in fact sometimes you can do it without it costing any more and so I'm just gonna step through some of the things that we do really in our normal everyday design for each each house that we that we are designing these days this conversation happens with every one of our clients I'm just gonna share kind of what we do and what we have done I also was fortunate enough to be a speaker for the SunShot initiative it's the Department of Energy they were there looking for ways to advance photovoltaics and so I was one of I think six six speakers that flew around the country presenting a one-day seminar and I've thrown some of those slides into here that wasn't necessarily geared towards residential that was more commercial but some great information about photovoltaics so including this this was one of the slides so we know that our buildings use 40% of the primary energy in the United States and we use 70% of the electricity so that is a huge amount and that's that's why that's why I do what I do because I want to reduce reduce the amount of energy that we use and we can make a huge difference in our environment in our energy use in the United States by concentrating on on buildings I'm glad other people are concentrating on things like automobiles and and how we generate that electricity and all of that that's all very important as an architect I can make a difference in the buildings and as the general public who lives in buildings and uses buildings we can all make a difference through our energy use in the buildings especially if you are embarking on a design project construction project paying attention to these things is is very very important so what we're going to talk about today is we'll start off with a definition of what net zero energy is and then we're gonna go through four four critical steps that you need to go through in order to create a net zero energy home and it's really not any different it's also applicable to commercial buildings it's really the same the same thing and then we'll close out with some photo book photovoltaic information and I'll show you a few more projects that we've done at the end so definition of net zero energy one there we go I like the developers definition I get this all the time they think they've created a net zero energy building because they put some photovoltaic panels on the top of the house and they know that will offset all of the electric usage in the building in the house and it's like well you got partway there Pat them on the back it's a good thing but unless you've got a fully electric house and you're doing all of your especially heating in our environment with electricity you're not going to get to net zero energy so we've got to we've got to get rid of that natural gas usage and then and then offset all of the electric electric usage in the entire house or building then we're at net zero energy so California I don't know I just got to pick on him a little bit they came out with this great statement that all homes by the year 2020 have to be net zero energy and I was I was excited I thought that's great way to go California and then I delved into what they mean by net zero energy and they kind of just they kind of squirrel dit around a little bit and they they made it so that when you generate energy at the peak time of day when the grid needs the energy the most they give you a huge boost for that so they count the energy more and then when you when you draw the energy back off the grid late at night you're you're drawing at a at a lower rate so they're it's not true net zero energy I think it's good that they that they're taking the stance like that but I wish they wouldn't call it net zero energy because it's really not it's close you're getting closer and and and that's not a bad thing this the definition that NREL actually uses is based on source energy now that means that they're going back to how the energy is created there they're looking at at the the power plant where the electric electricity is generated and what that does with source energy is if you are using say natural gas and to heat your home the NRL's definition of net zero energy allows you to offset that natural gas usage with electric generation so you generate more electricity than you need and put it back into the grid but then you're using natural gas I really don't like that definition I realize it's you know it's you know maybe necessary in some instances but I would rather push our our designs to using only electricity and then we generate all that electricity that we need annually on-site so that's my definition is much simpler it's just generate the energy that you need on-site use it on-site use the grid as your you know battery per se so when you generate more energy than you need you put it into the grid when you need it at nighttime when you're not generating electricity you pull it out of the grid and on an annual basis you're using the same amount of energy that you're creating that's where I think we need to be for our definition of net zero energy so some other terms that you may hear I like net zero energy it just kind of flows out pretty easy you hear people talk about net zero building's net zero net energy putting the zero first or zero energy buildings also people talk about zero carbon the carbon footprint being carbon neutral is a great very similar term energy positive you see that sometimes I know Steve Stevens always says that he's got as his home has built up now to be energy positive where he's creating more energy than he then he uses and high-performance buildings Living Building Challenge and passive house are all interrelated and and great movements that that are using a lot of the things that we're talking about when we talk about net zero energy so that brings us to these four steps that we go through and in our in our designs and that these absolutely I put this in all caps and then I was like no that's not good enough and I made it red that's like yes we absolutely have to do these things in this order so we've got to design the house really well to use the Sun we've got to make the house really efficient the exterior envelope the walls the roofs good insulation tight and then we need to look at okay how are we going to heat and cool the building and and use as inefficient to the system as we can and then and only then should we talk about electric generation so building a a building that doesn't perform very well and then slapping some photovoltaics on it really is is doing a disservice to everybody you're not using the PV well you put you need to put the money into good design good construction and then and only then are we ready for for photovoltaics I think that is extremely extremely important so our first step this is it should be really old hat I mean back in 1981 when John's house was built you know this is this is was the state of the art this is what they were working on that passive design and we can't forget that that is this is sustainability 101 we've got to we've got to design the house to use to use the Sun to use breezes to use passive passive heating passive cooling and that is that is where we where we need to start so here I like this diagram this is this is a house that we designed about 10 years ago it's off-grid and real typical for us when we start designing we do we start with two schemes so we do one one scheme that maybe that's sort of what the owner expects and then we do another scheme that pushes the boundaries and does something they don't expect design the house in a totally different way well here we had a we had a homeowner they actually have a kitchen kitchen subcontracting business and so they do designs a lot for the kitchens and they thought well well we can design a house and this was basically their house design we had to fix it up and make it work there stairs didn't work and things like that but but we we took their design and and drew it up the best way we could but we knew that design was just not gonna work very well but that's what they wanted so we gave them we gave them what they wanted and then we did a separate design so north is straight up in this we we have to draw the house long in the east-west direction that's this is just I'm sorry if this is repeat for a lot of you but this is passive solar design 101 here draw that building out long in the east-west direction that maximizes the South Face and then you want to minimize the east and west because that East Sun when it comes up in the morning is pretty harsh when it sets in the West in the afternoon it's really harsh overheating houses is very common in the Denver area because people have these great west views of the mountain right and and they they want to maximize that so we wind up with these two stories of glass facing west and the blinds are all pulled so you can't see out the windows at all right so minimize those West windows minimize the East on the north do very very little openings at all just have really good insulation open up that south south base fortunately they had a great south-facing view this is up in Granby and so fortunately I can't tell you how many times when we've done this the the the owner still wants the design that they drew up fortunately we had a more discerning client and they did proceed with with this design and this is what they wound up with so there's that long east-west direction it's off grid so we had the photovoltaics generating the electricity use in the house and an a fair fair amount of south-facing glazing it's easy to over glaze too so you do have to watch out for that but then here's the beauty of the south-facing Sun and when that Sun is in the summer when it's blazing and we don't want it in the house it's up at a 74 degree angle off of the off of the ground so a very small overhang you can see a very small overhang will cut out and not allow that Sun to enter enter through the windows so just properly sizing the overhang cuts out that summer Sun and then you come to wintertime and that Sun is way down low in the sky at 26 degrees above the earth and and that overhang is not cutting out the winter Sun so allows that allows that to flow in and when we do have a lot of glass on the south side we do a lot of shading devices H and H metals here is a local company that builds some really nice metal shading devices this one is kind of one of our standard details built out of wood but it shades the shades the Summer Sun allows in the winter Sun but shading those south-facing windows is very important we want the Sun in the Sun in the winter we don't want it in the summer also I should say that programs everything is drawn now in full three-dimensional models we use Revit kind of the industry standard and that allows us to do shading studies so we can we can create these models and we know exactly when the Sun is going to hit the windows and we time that and that really that really helps us helps us tweak that and get get the design right so and last I would say I daresay this is becoming less important I used to be a huge advocate for thermal mass this is a home where we use the concrete floor as a slab on grade this is ground polished concrete we have we have a lot of stone in the house to capture that sun's energy and we're we're putting less emphasis I would say these days on thermal mass it's still definitely something to pay attention to it's gonna make your house more more efficient and and so that that thermal mass what happens is that the Sun comes in heats up your thermal mass and and sort of soaks it up and then that evening as the Sun Goes Down it's getting cooler now that those the the thermal mass whether that's in your water tubes we've done certainly stone and concrete floors even chip creat an inch and a half of Crete with tile on top it makes a nice thermal mass that radiates off the heat at night and so it makes your house more comfortable because when that Sun does come in even in the winter I don't know if you've been up in any houses I remember I was standing in one at 10,000 feet that had an over glazed South wall and it was middle of winter still unbelievably hot in that house and they are asking me what do we do one of the things they could have done is they could have had thermal mass in there to soak up that that energy so that it would radiate it back out at night so once we've once we've designed the house we've got the correct orientation we've shaded the South Sun we allow that South Sun in the winter got some thermal mass now we're ready to start thinking about the thermal envelope we call it so that's the exterior walls the roof the the basement and we need to we need to do a really really good job of of limiting the amount of exterior environment that's going to be transferred inside right we want to if we want to keep that cold out in the winter we want to keep the hot out in the summer this is our rule of thumb and so the 5 10 20 40 80 you just double it each time you start with our five for the windows so that's a you've a lieu of 0.2 is so it's the inverse the u-value is the inverse of the r-value if you hear people talking about the u-value of windows or indoors any openings are measured that way so we like to get that that to about an r5 or better the below slab insulation and our 10 so down in your in your basement we use two inches of rigid insulation below the below the concrete slabs are 24 the walls below grade so you've already got you know that that that that wall once you get down to four feet or so deep that that soil outside is going to stay at 40 45 degrees even during the winter so you don't need as much insulation when you're below grade walls and then the above grade walls we shoot for an AR 40 I'll show you a few ways that we do that and then for the roof we want our 80 if you can't remember the 5 10 20 40 80 just double whatever code says you're supposed to do so that's that's a good rule of thumb and I'll tell you you get contractors I do we have any contractors in the room yeah some contractors not this one will will say what the heck you know I've gotten calls saying hey can I eliminate that insulation under the slab we really don't need it code doesn't require it yeah why are you why are we putting so much insulation in these walls I can save the homeowner you know X number of dollars because I why why do you want this much insulation in the roof I these are our rules of thumb we feel like once you start getting above those maybe maybe you are spending more money than you really need to but insulation is cheap and it is really inexpensive insurance to get to get the house that is going to perform well for you and it's going to make it more comfortable too it's gonna make it quieter and and you're gonna use less energy heating and cooling so lots and lots of benefits so some of the insulation methods we've used structural insulated panels insulated concrete forms I've got pictures of a couple of those double stud wall construction that was this it's hard to take a picture of double stud wall it just looks like a bunch of studs but what we do is is just have two rows of studs with about an inch in between and that gives you a nice eight inch thick or nine inch thick wall eight to nine and fill that we like the bibs the blown in blanket fiberglass insulation you fill that up and you get your easily over our thirty and go a little thicker you can get to our forty or do some exterior rigid insulation but framing is really pretty inexpensive and you only need a two-by-four frame for for a house we went to two by six years ago just to just to increase the amount of insulation so go back to that two-by-four for your structural wall on the exterior put another 2x4 wall inside of that get a nice thick wall fill that with insulation and it really is very inexpensive you'll have a little cost savings dropping from two by six to two by four for your structure and then you'll have a little more cost in the in the second framing wall inside however framing is is really not a big portion of your of your overall budget that and you're only talking your exterior walls you know you're not increasing the width of the injury whilst Jim I wouldn't I wouldn't recommend putting gypsum board in the middle of the wall because then you're gonna affect how that wall can dry out to the inside or the outside that's that you're gonna have a potential of trapping some moisture in there I think well it with that one inch in between the the one inch or more in between the the two sets of studs you've got a full thermal break then so exterior rigid insulation is another way to get that continuous insulation but by by by having the double stud you're also and then we offset we offset the studs up as well so that the studs on the inside wall don't align with the studs on the outside wall so you get really good continuous insulation throughout the entire wall yeah wood doesn't have a lot of our value to it we haven't we haven't found any problems with condensation is that because of the the bibs insulation we actually don't like if you're gonna use a vapor barrier on the inside we certainly recommend the smart vapor barrier is not like not like the six mil the screen that we we typically do not do a vapor barrier we just use the the code requires something and we put on our drawings that the paint is the is the vapor barrier yes on the on the outside we would have that's your that's your moisture barrier it's not a not available the house wrap tie back on the outside was the question yeah yeah if you're doing if you're doing a would say trimming out everything in wood you're gonna have a little more cost in that and no but if you're just wrapping it with gypsum board no there's not yeah uh-huh yeah that can run a little bit but it's really just one extra one extra piece of trim around I mean yes there there is cost associated with that let me just go to some of these other so continuous exterior rigid insulation we love to use that it you have to be careful about what your what your siding is going to be so that's once you put up the once you put up the stud wall and then you put exterior rigid insulation so this companies zip has developed a sheathing that has the continuous insulation built into it and I'll show you a picture of that and straw-bale that's always a good a good option so this is these are structural insulated panels I didn't have a good picture of it of them actually putting putting one up but we did it an entire school down in Castle Rock using these and so this is just by a styrofoam insulation with a sheet of OSB on either side so that's your entire wall insulation structure we just put the interior finish on put the exterior finish on put house wrap or building wrap on the outside but that makes it a very tight well insulated building very quickly insulated concrete forms put the puts two layers of insulation on the on the outside edges and then you fill the center with concrete it's used a lot for foundations we've built entire houses all the way up to the eave with with ICF's this is just a picture grabbed off of Fox blocks website but there there are others and if you don't like polystyrene which we do you know like to stay away from there are a couple of companies that that make that make ICF's out of wood and concrete so they're a little heavier block but fast wall and Duracell are two of those that we've used just yeah the the environmental aspects of one as it's being as it's being made is it and and yeah and and fire certainly is it's not gonna perform well on a fire this is the zip system so if you've seen buildings going up around town the that are all green and then they've got this black tape on it so that's that's zip what they do is they take they take insulation and they bond their OSB sheathing to it and then they and then they have the this is basically your house wrap which is already bonded to it so it all comes out contractors some contractors like it do you like it bill oh really yeah yeah yeah thing to try to move along a little bit more this is a straw a straw bale home up in Genesee that was built last year this was on last year's solar home tour actually you went on that and so once you get that once you've selected your exterior exterior your envelope as the contractor is building it we like to see them perform a blower door test so this is a door sealed up with a big fan and they're they're doing testing mainly you know we don't so much care about what the actual numbers show what we want to see is we want to see the the tester going around the house and with a thermal-imaging camera and making sure that any leaks are sealed up this is a great time during construction before you've got those the the final finishes on to go and make sure all of your all of your joints are sealed up of course you got to do it while you're building to but but this is a great test so if you make sure your contractor does that it's literally a few hundred dollars it's not not very expensive at all but that that combined with proper air sealing techniques all around the house as you're building it well air movement through through walls is just as critical as the insulation levels itself so once we've done that now we're ready to start talking about how we're gonna heat and cool the home and the other systems we're going to use so this the heating the space heating and cooling is going to be your primary energy usage but also hot water how you how you heat your water is going to be very important cooking clothes dryer these are all things that we typically in Colorado would use natural gas to do use natural gas to heat we use natural gas to create the hot water for people love a gas stove right and your clothes dryer you know for years and years we've always said natural gas is that the most effective efficient clothes dryer that you're going to have so so for heating and cooling and this is something that we've been working on trying to get away from this I would say this is a little bit of a crutch and almost all of our net zero energy homes to this point have used a ground source heat pump system for heating and cooling the problem is they're they're fairly expensive and we're we're looking at other ways we can heat and cool without having to go to the expense of a geothermal system however Todd back there will tell you that as long as we do a really good job insulating then and sealing the house and designing it for for passive solar that ground source heat pump system doesn't need to be that big and so you do drop that cost the ground source heat pump is also eligible still eligible for a 30 percent tax rebate from the from the federal government so that is going away in 2023 I believe so so get it well it lasts through the end of next year it's 30 percent then it drops to 26 22 and and then goes away so not going to spend a lot of time talking about these systems themselves the mini-split if you've seen this is this is kind of the typical what people think of when you think of a mini-split system and it's this little box they're coming down in price they're pretty efficient so so the the mini splits are great for small spaces maybe maybe can be used for an entire house you can you can use them like this all you can duct them so that this instead of having this which a lot of people would not want to see in their house especially in their living room we can hide those systems so I think this right here is actually that's the mini split unit and then and then run ductwork off of it so we can we can use those so that's an air source heat pump rather than a ground source heat pump is basically what the the mini split is has a coefficient of performance three which means for every one unit of electricity that you're putting into it you're getting three units of heating or cooling out of it so it's a fairly efficient system then the heating the water heating we have been using more and more of these style l-tron is a great great brand of it's a heat pump water heater sometimes our mechanical engineers don't like them a lot because what it's doing is it's it's dumping cold into the into the space that it's in but if you're careful about where you put it and if it's sitting in a in a space that you have other things that are kind of generating electricity it can be a pretty nice nice arrangement so the thing about these they're an air-source heat pump also just like the many split and just putting that that energy into creating hot water rather than heating or cooling air they run around $2,500 so they're not that inexpensive but then it's it's a much simpler system you don't have any you don't have the venting for that you would for for natural gas or propane and literally you plumb it in and plug it in and it's it's ready to go so oh okay great I didn't know that so 20 are they down that low now yeah mmm yeah yeah careful of the brand make sure to check it out stable l-tron is one kind of pioneered that great great product but there are others out there so on all of our sustainable homes we used to push our clients to install a solar solar thermal system so solar hot water rule of thumb not not very long ago was to flat plate solar collectors would would generate 75% of the hot water needed in a home cost about $7,500 to install and it's a good system we called that the the workhorse of of solar active solar energy and the problem is that you're spending seventy five hundred dollars for that system and then you have to have your backup hot water for when when it's not hot or you've depleted the the hot water from your solar system so you're still installing another another source of water heating with this you are you're only spending twenty five hundred dollars or less and and and then you put a couple more solar panels on your roof to generate the electricity to operate that now you've got now you've got a fully sustainable electric system and for a lot less that's creating a hundred percent of your your hot water needs so we really really like this yeah so cooking I'm not going to spend long on this but the the induction cooktops are they basically work they provide everything that that most people love about gas they're instant on instant off and they're all electric so we we introduce our our clients to the to the wonders of induction cooking and for clothes drying there are heat pump heat pump clothes dryers out there now basically you know using the same sort of technology as many splits and the the heat pump water heaters so so now when we've done all of that now we're finally ready to start talking about generating electricity on-site and almost a hundred percent of the time our conversations are going to be around photovoltaics we have looked at small small-scale wind it's still a tough sell maybe if you're if you're out out somewhere and and really do have good reliable wind but but this is this is our our mantra is that we need to do we need to everything for those first three steps before before we start talking about photovoltaics so we don't we don't want to just slap lipstick on a pig or however you want to call it we want we want to make sure that we've got that house really well designed and all other aspects before we before we incorporate photovoltaics so just a little bit little bit of information about photovoltaics many of you I'm sure familiar with this your photovoltaic panels typically on the roof you know we're a lot of times we're putting photovoltaics ground-mounted though on a on a very simple racking system if you've got a little bit of land in their spot to do that especially up in the mountains ground mounting is nice because you can you can get the snow off them you can clean them very easily you're not trying to climb up on the roof and and if you want to see some nice ground mount once check out Jim's office down on South Golden Road you just lay in sitting right there you can walk up to them and look at look at how he's mounted those but you've got the photovoltaic panels and then you've got this is the inverter and so all those panels are running - in this case a single string inverter and then you've got your your service panel so these are as your you know just your typical circuit breaker panel and then you've got the smart meter and the smart meter is key this isn't we're lucky in Colorado that I think every utility in Colorado offers smart metering it's not still not the case all the way across the United States so this smart meter allows allows the electricity to flow backwards and and reduce your just kind of remove remove from your from your record any energy that you've used any electricity that you've used and then when you're using when you're using the energy from the grid it flows you know the direction we'd normally expect a ammeter to so those are the those are the four parts that you need in order to make that happen there are some options with inverters not going to go into that today but certainly your your solar installing company will be able to recommend the proper inverter string inverters or micro inverters don't see DC power optimizers very much on residences but and so here's just a few quick facts about a X&Y it is such a great option now if you go back to 2009 okay and this is the the number of installations that were being done in 2009 and this is the cost of the photovoltaic installation so more than seven dollars per watt so we weren't we didn't have that many of them and then through 2010 11 12 13 you look in 2014 we're down to just over $3 per watt install we're sorry we're at 2 to 20 per watt I believe this is these prices are commercial not residential but as that as that price dropped we saw more and more installations come about and and now you know down under $2 per watt we usually we use right now about $2 per watt as a rule of thumb for what the what the PV installation is going to cost you but this is why this and this of course have a direct relationship and and that is why it makes sense to install photovoltaics now here's this would be installed kostya installed solar PV capacity solar PV prices another way of looking at it so this is the greener the residential installations the orange are non residential commercial and then the the blue or utility grade installations but you can see how they how they have grown to now and how they are continuing to estimate that affordable tags are going to get more and more popular it's not leveling out it's still it's still taking off here is the this is information taken from the SunShot initiative from the Department of Energy so this is where we are right now so here's the residential you can kind of ignore that commercial and utility for this talk but back in 2010 this is a the LC yeah so the the the cost of of installing photovoltaics back in 2010 versus where we're at and this was 2016 which was the latest year available at this time and then their goal is to bring bring those costs down half again in by 2020 and half again by tooth by 2030 so if we if we can reduce the cost of photovoltaic installations by another 50 percent or more then we're really gonna be it's gonna be yeah just like everyone's gonna be driving electric cars everyone's going to have photovoltaic panels either on their roof or it got a home like mine that's in a very heavily treed area I'm looking forward to the city of gold and building their solar gardens so that we can put the money that we would have put into photovoltaics on our house where they don't work into the solar Gardens where they will work so that's just knowing know that the Department of Energy and other really good people like NREL are working to bring those costs down even further we're not done yet that doesn't mean wait it just means that as as we go on further that you will see those costs drop and this is another slide that I really I think this is just fantastic I think very few people know and understand this so this is how much energy is generated from a photovoltaic installation this happens to be in LA is where they did this test but this is using I think you can ignore this top bar because that's a dual tracking system like you see up on cell Table Mountain at NREL facility so we're probably we're not going to do that on a house so let's just look at if you have if you just have a fixed panel and it's facing south you're gonna generate 1566 that's kilowatt hours of annual production out of one a one watt of a panel but in any event the units aren't really important it's that that and kind of an optimized south-facing panel tilting is gonna generate 1566 units of energy right then you look at west and east for Colorado you should flip these but you can see if you you tilt that panel this would actually in Colorado be due east this would be due west but if you tilt that panel due east instead of due south you're only losing about 10 percent of the energy 10 percent so put in one more panel up on there and you know if you can't get the panel's facing south it's okay you know actually we like a little Eastern tilt to our panels because we get that nice early morning Sun and the afternoon it gets cloudy you got the mountains to the west blocking that last little bit of Sun so facing a little bit of East is okay but facing due east is just fine don't face them North like they did on up on highway 93 they're just one more second but then here is here's the beauty look at this no tracking installed flat just a on a flat roof just put them flat we like to have a little bit of tilt so you know snow and rain come off them and they keep a little cleaner but there you're at the same you're you're a 10% penalty for just putting them flat so people get all up in arms about oh it's got a face south it's got a face south it doesn't and you're still gonna get a lot of energy production out of that so now question I don't understand yeah I'm sure it's generating a little in the summer when the sun's high but yeah all right so that's kind of the end of what we do why we do it just a few quick images these are two homes that are on the the tour I keep calling it the solar home tour what does it call John the green home tour okay great and so this is in Morrison and a great really fun fun house but this is net zero energy I'm not crazy about how they installed the solar panels you not supposed to see him we designed them to lay flatter down on the roof that's how they got installed they didn't ask me they didn't follow our drawings but it works well for the solar tour this weekend heard that the green tour this weekend so you can actually see the panels that a really really wonderful house really right inside now this is an example of a their views facing north so we're we have these south-facing clerestory windows bringing in that South Sun so you know it happens we have clients who buy North facing lots and there's yeah we can't can't always control that this house another net zero energy house this has a 10 kW array don't tell Excel energy but Excel has their little calculation of how many panels you're allowed to put on the house and we had designed a 30-30 panel system so 10 kW and Excel came through and said nope you can only put 28 panels but they had already bought all 30 of them they had already installed them and so we did some quick calculations because it's based on square footage and we showed that well that crawlspace has a really tall Headroom so maybe we can call that part of the house they were already using it for storage and things so and so we got them up to where they could have 29 panels so they only had to remove one panel and I don't think it ever got removed yeah Excel doesn't want you to generate more energy than you need they don't want to they they don't want they want to generate the power they don't want a lot of competitions so I honestly don't know what Excel does for if you generate more power than you use other than you'll annualize you'll kind of but dig at ok yeah so they if you so this was an existing house so we we were a little limited on what we could do but we did use an exterior rigid insulation for continuous insulation there this is that straw bale house I showed this image before this was on the tour last year so the back wall is straw bale we also use Duracell ICF's on that and this is their I think is just under a 10 kW installation and is the interior a nice house up in Genesee and so they're very nice homes people they spent a lot of money on these homes but they're you know not not outrageous amounts and certainly the little bit of extra they put into the into the systems to get to net zero energy are pale in comparison to some of the things they spent on an $8,000 stove and you know things like that thanks John this was on the home tour three years ago this is actually a duplex so this is the this is a single-family home three-car garage with a large accessory dwelling unit that she rents out I think this is about a 9 KW system's got a ground source heat pump and she claims that it's it's it's showing that 0 each year so this house this was our first house that we did double stud construction on and worked out very well they were not a fans of photovoltaic we did design this roof to have photovoltaics on it and if they put the photovoltaics on it would be net zero energy so he'd call this net zero and energy ready yeah and this one was on the home to her was that last year two years ago I think when it was still under construction this is we call this like our almost net zero energy this does happen the the contractor got involved and said hey you're spending a lot of money on that ground source heat pump we can save you a lot of money by just going to a really efficient gas fired heating system with a good you know high seer rating on the the air conditioner and by the way we'll install two of them and and so they drop to a 4 kW system so it's one of these it's a Net Zero electricity building but it uses gas for the for the heating so it's kind of bummed about that but it's a beautiful house and double stud wall construction sips for the roof well well insulated and is performing performing very well and then just to to last slides I think these are kind of interesting to compare this is a school in Castle Rock that we did a couple of years ago opened a year ago and all of these rooms are designed to have photovoltaics on them in the future this one because it's gonna be shaded south is that way because this was gonna be shaded we didn't care about how many pentru penetrations and they kind of went wild you can see we just had one penetration there one there for bathrooms and so these are all set up for future future photovoltaics if they could have spent five hundred thousand dollars on the photovoltaics they could have a very near net zero energy school that sounds like a lot of money but it's a nine million dollar school so you're talking about five six percent if they could have increased their budget by six percent they could have they could have put the photovoltaics on there being a school they don't pay taxes so they don't get the tax benefits makes it a little more difficult no this is residential discussion but they also in Colorado we have demand metering which usually counts for about half of your bill and photovoltaics really aren't going to cut that down so it's a tough sell sometimes between the the between the not having the tax breaks and still having to pay half of your utility bill because of the demand metering makes it a really long long payback so I don't know at what point demand metering starts yeah we I mean our our office is small also and we don't have demand charges on our bill I think you have to hit a certain threshold anyone in the room no but any any more information about demand metering it's really not part of this discussion so yeah yeah yeah do it a PPA power purchase agreement or or lease yep yeah there are there are ways around that but doesn't help with the demand demand charges but this is he well no they take a couple months off in the summer yeah yeah yeah yeah and so this is a 40,000 square foot school and we need to cover all of those roofs in order to get net zero energy by the way this is a variable refrigerant flow someone somebody brought that up it's kind of like mini split for commercial applications but it is electric heating and cooling and this is a school that I designed on a mission trip in Liberia Africa nearly at the equator and very very little electric needs no of course no heating no cooling either other than ceiling fans running and this is more our electrical engineer told so that's more than enough photovoltaics if they can get them to run the entire school and make that school in that zero energy so and this is an eighty thousand square foot school so I just think it's interesting you know keep our environment with the the amount of heat that we need it takes it takes a lot of energy and so you know driving those energy moves down and then before we we do the photovoltaics is great but you know we're always going to need in our environment we're gonna need more than you do in California or in Liberia to get to net zero energy but we can do it the technology is here it should just be a no-brainer and so that's that's why we we do what we do I think that's yeah that was the end of that [Applause] you

Channel: Colorado Renewable Energy Society (CRES)

Views: 142,495

Rating: 4.7684708 out of 5

Keywords: Net zero, passive house, architecture, building efficiency, solar power, mini split, ground source heat pump, NREL, Peter Ewers, off grid homes, passive solar, home insulation, distributed solar, energy efficiency, carbon reduction, passive design, solar home tour, New Energy Colorado, CRES

Id: st-Gd1ZcFyM

Length: 53min 14sec (3194 seconds)

Published: Sat Oct 06 2018