The Crazy Truth About HVAC Sizing!

hey guys before we get to the video please click that subscribe button hey guys joshua griffin air serving the middle peninsula and the northern neck of virginia and i wanted to do a video on one of the most controversial topics in the heating and air trade and i'm going to do it i'm going to talk about heating and air sizing and you know before i get into all this i do have a few disclaimers that i want to mention uh the first thing is i'm only going to be talking to you know you guys that are homeowners residential applications i know you folks that are up against industrial commercial type challenges it's a whole nother animal totally different set of rules and we're not going to be talking about any of that in this video so we're only going to stick to residential stuff and my other disclaimer is every market is different some of the things i'm going to run through is controversial because every area is different every area of the country every area of the world and you're going to see different types of challenges meaning humidity and you know sizing and other conditions like where the units are located and maybe what their atmosphere is subject to so that's the disclaimers and so we're going to talk about a couple different things we're not just going to say you know air conditioners are too big or too small or whatever we're going to go through a list here and we're going to talk about things that i think that you know you need to know maybe some things to think about but again because every area is different i would defer to your local expert your local heating and air guy that does this for a living i can tell you that there are folks that come into our market where we're located in virginia and they'll oversize systems or they won't understand that some of the challenges we're up against another area of the u.s i always hear about is the northwest part of the united states because the air is more of a cooler uh more humid clammy type of feel and so you guys have you know challenges that we don't have here so let's go through this the first thing i want to just kind of touch on and again every area is different but i want to just say in general just starting out if we're talking about heating and heating alone you have a little bit more i would say play a little more cushion than you will when we get to talking about air conditioning and some of that stuff so what i mean by that is i see systems all the time that you know for the heating it's actually oversized for the space for one reason or another and it's not the end of the world again that's just a general rule of thumb so if you know if you have electric or some sort of fossil fuel being burned or however you're heating your home i would say that in general if it has more btus than what that space calls for it's not the end of the world and in fact i can think of certain applications where they intentionally oversize things one thing that just comes to mind is mobile homes we see mobile home furnaces put in they're high static applications and we'll see them install really large heat kits in these you know furnaces uh they're straight electric and all that good stuff but you know i think the thought process is you know we're gonna be burning a bunch of electricity right here let's heat the home as quick as we can and get that thing off uh you know so it's not the end of the world is all i'm saying if it's a little oversized uh you know it's not the end of the world in general another thing i would just say is you know if you have other types of heating systems like radiant floor hydraulic heating things like that again i wouldn't lose sleep i've even been on projects where you know they're building one wing of the house and they're gonna heat that with this system and another wing or something like that isn't done yet and they're wondering you know if the system's gonna be oversized and heating it should be no big deal in most cases again every market is different area every area is different i keep saying that because it is i would just defer ask your local expert and see what they think the next thing i just want to touch on before we move on to air conditioning and heat pumps is dehumidifiers i love dehumidifiers and talking about them because i've seen a lot of misinformation out there but again i would say as a general rule you cannot oversize a dehumidifier you can undersize it and it just can't reach the humidity set point that you have it set at depending on the market and all the conditions and thought you know all those things like that but you can't really oversize a dehumidifier in most cases because all it's going to do is it's going to remove that humidity get that set point you know where you have it set and should be no big deal so let's talk about the big elephant in the room one of the most controversial topics in the heating and air industry and the reason i say it's controversial is i hear all the time and it's true with my experience as well is most systems when we go to someone's home their system is not sized properly for their house in our particular area i see them oversized a lot but you know you'll see different times when it's oversized or undersized it's not sized properly and why does that matter well in general if a system is undersized for a home or space then you know obviously it's going to struggle to keep up in those extreme temperatures so you know if you got a hot summer day and you got a two-ton system there and it should be a three-ton it may struggle to you know get that heat down and reach temperature and you might say well what do you mean by tonnage all we're talking about is btu so when you hear folks say oh that's a two ton system four ton system whatever all they're talking about is the capacity the btus that that system makes we'll send folks different proposals sometimes and they'll have different seer ratings and they'll say well will this system keep up well they're all the same capacity you know we're giving you the properly sized system here also keep in mind if we're talking about heat pumps again i've seen houses where the heat pump may be you know undersized or too big or whatever and in heating mode and you know you have those challenges but then you get to air conditioning mode and you're back up against the same challenges that you do with straight air conditioning and so just keep that in mind that all the heat pump is is a air conditioner that runs backwards in the winter time to provide heat right and so in that summer time it still has the same challenges if you undersize it it won't reach temperature that's undersizing what happens if you oversize it uh you know we talked about heating oversizing it and it'll heat the space really quickly and shut off and that's not necessarily a horrible thing why is it such a big deal when we're talking about air conditioning well the first thing is it will make the system not dehumidify enough and in a lot of markets especially the market that i'm in that's a big deal pretty much anywhere on the east coast that's a big deal the further south you get the bigger of a deal it is i remember years ago i worked for a property management company and we had a a property down in florida that was having all these mold issues and they found out that it had to do with the air conditioning in the apartments and all this it was just a nightmare and so all i'm saying is if it's oversized what happens is the system will run cool the space really quickly it doesn't remove enough humidity from the space where heat meets cold right so you got these hot walls hot furniture all this heat and now you've cooled that space really fast you're gonna have humidity issues and you know you can remedy that with dehumidifiers and things like that but hey why not size your system to start with properly right so that's the first thing and then you know honestly i think that's the biggest thing but if you're in a market where you know humidity is not an issue it's dry air you know maybe you're out in the west somewhere and it's basically a desert and that's not such a big deal then i would just say that you need to worry about it for short cycling and things like that so you know if the system's oversized for the space it cools the space really quickly you're getting this short cycling instead of it's actually a lot of folks don't realize it's less efficient for that system to be on off on off rather than being sized properly on a hot summer day and just running for long periods of times instead of having those spikes in energy hopefully that makes sense you can oversize it and you can undersize it in a lot of markets now that we've said all that i do have an exception to that rule and that is we are seeing if you have a system that are that is three things three things first of all it has variable speed and or motor okay indoor fan motor is variable speed the second thing is it's an inverter system so your outdoor compressor can ramp up and down right and then the third thing is it's communicating system where they can communicate with one another i know we've actually installed some of those bosch products and some of those products that are coming out and i'm not saying there's anything wrong with them but you know even though they're inverter technology and they're more efficient you still have those same challenges of sizing and all that good stuff but when we're talking about the three things i just talked about the system is variable speed indoor inverter outdoor and then communicating then that system you can technically oversize it and it be okay and what i mean by that is if it's running at 100 capacity yeah it's oversized but it's rarely gonna do that so if you have everything set up properly that system's gonna at times just barely be running cooling the space removing the humidity and keeping you comfortable and the way i can definitely tell you is check out a lot of the ductless systems that are being installed today and i'm not talking about those el cheapo ones you can find online i'm talking about the guys that are the best at what they do guys like daikon mitsubishi and then some of these other folks like fujitsu that are coming along so a you know a great inverter system communicating ductless system and we're seeing those you know work tremendously in spaces that technically it might be oversized and things like that now again i know i'm throwing blanket rule of thumbs that's why a lot of this stuff is controversial and all that good stuff i'm sure someone will comment on this and you know i get heat in there guys all the time telling me why i'm wrong and that's fine but i just i'm giving you a few things to think about when it comes to that stuff the last thing i'm going to say before we wrap up is ductwork again there's so much misinformation out there ductwork sizing is probably just as important as the sizing of the system you know i don't think i mentioned but if you're actually sizing a system for a home doing a proper heat load calculation getting a contractor that you know knows how to do that and figures out the exact size that that home needs to be the same would be true for the ductwork sizing it properly for the proper amount of static and proper amount of airflow and all that good stuff uh you know just real quick if a system has duct work that's undersized then you know you're going to have some more velocity through there but the system is going to be cut down on capacity because the air can't move across that coil like it should and you know imagine if you had to breathe and you covered you know half your mouth or even three quarters of your mouth and you had to breathe through that small hole all the time same concept so you got this fan motor trying to either pull air through a return that's too small or push air into you know duct work i always think about like garden hose imagine a garden hose that's kinked right and it's you know you got all this pressure building up so you know you might put your hand over the vents and if it's under size and say oh you know it's it's blowing my curtains but you what you don't realize is you've actually lost capacity and of course nobody changes their air filters as often as they should and you know now you're losing even more capacity and you know we've seen that a lot you know where folks are just not moving enough air through there and they're having capacity issues they're having issues with the evaporator coil freezing up and things like that and the last thing i'll say is if the ductwork is undersized is it's just harder on that system you know the fan motor especially it's trying to it's trying to push all that air through there and it can't you know it's doing what it can but you're putting a lot more strain on that system than what it should have been you know designed for if it's oversized uh now again we're talking about residential so you can technically i when it comes to my returns i'll oversize them a little bit because i'd rather be too big than too small but when we're talking about the supply side and we're pushing air through that duct work that ductwork if it's oversized it actually it's almost like if you were to try to if you took those deep breaths like right you take a deep breath and that system's trying to push this air through this system with too big of duct work the biggest thing is you're not going to get the velocity through those ducts that you should right so it's pushing air and you but you don't have the static and then you start getting to some of these vents that are a little further away from the unit and things like that and you know you're not getting proper amount of airflow you have one of those homes that you know the one room is colder than the rest or warmer than the rest or things like that i can't tell you how many times that has to do with ductwork sizing either it's too big too small something's wrong there and just getting that corrected takes care of that you don't have to go adding a ton more duct work or adding a ductless unit to you know supplement it's just a matter of getting it sized properly and preferably sized properly from the get-go so hopefully that makes sense if you have any questions or suggestions add them to the comments down below i really appreciate you watching thank you with all that said if you're in our coverage area and you are in the market for a new heating and air system give us a call we'll give you a free estimate we'll give you a great warranty the best warranty i think in the area and you know we'd love to earn your business if you're not in our coverage area but you're in the market for a new heating and air system before you spend thousands check out my website newhvacguide.com and the whole idea behind this website is just like a cpa would help you with your taxes this is going to help you with the purchase of in a lot of cases the third largest investment that you're going to make behind your house behind your car a lot of folks their heating and air system is the third largest investment with that said we put so much information on there i it's almost as if i wrote a book decided not to because it you know as soon as i do it's going to be outdated new technology comes out new all kinds of information comes out and so this website is like a book but it's constantly being added and changed so you know we even have a whole page called no-no's things to stay away from things that you want to avoid in your pursuit of purchasing a heating and air system and we just have this step-by-step guide so new hvac guide dot com and lastly please subscribe if you haven't already we really appreciate your support and stay tuned for more videos tips tricks and appreciate it thank you

Channel: HVAC Guide for Homeowners

Views: 79,276

Keywords: hvac oversized, heat pump oversized, heat pump undersized, ac too big, ac too small, hvac system oversized, new hvac oversized, heating oversized, air conditioner oversized, heat too big, Ductless oversized, hvac sizing, hvac undersized, ac sizing, sizing an air, sizing an air conditioning system, air conditioner sizing, furnace oversized, ductless sizing, ductwork sizing, duct oversized, heat pump sizing, dehumidifier oversized, Furnace sizing, Dehumidifiers too big

Id: Q4DvK_NPSL4

Length: 16min 47sec (1007 seconds)

Published: Thu Mar 18 2021