 Welcome back, I'm Nate Adams, and this is the fifth part of the Electrify Everything course. This is a third module, so HVAC, this is the hard stuff. So everything else is really just changing appliances and relatively easy stuff to do. HVAC, the easiest way to look at it is like an organ transplant. So there's a bunch of little things that you really want to know, and like we've discussed in the past, particularly in the scaling piece of this, if really good experiences aren't had by both the homeowners and the contractors, we're really going to struggle to scale. Probably likely to kill it, not unlike how 1980s diesels were so bad that they damaged the reputation of diesels in the United States for years and years and years while they became super popular in Europe. That turned out to be a bad thing, but it's still a good analogy. So last time we talked about resistance heat and how it is not actually a bad thing. This is an actual picture that I took of an actual client unit running full tilts, that's 15,000 watts burning right there. So it's a useful tool, we're going to touch on that again here, but what we're really going to focus on is called static pressure. This is the most important concept that you probably never heard of and a lot of HVAC contractors aren't that familiar with this either, but it is utterly critical because if you don't keep an eye on this, your system is going to be really noisy and you're likely to have failures within one or two years after install. That's bad. You don't want to be replacing these fan motors, they're expensive. There's all kinds of other things that go wrong with high static. You'll severely limit the life of your system with high static. And then we'll touch on surge protection at the end, it's pretty quick. Okay, so here's where we are in the core syllabus. So we are down in part five and we are talking about important details. And this is a really, really important detail. And I expect that this will get a fair amount of play because it's an unusual concept that not many people are going to know about and this is a really common pitfall. So if you happen to be here because somebody sent you this, look for the link below to sign up for the rest of the course because this is just one small piece of what it is. But this is a really key thing and this is something that not many people know about and it's really important for providing good experiences. Okay, so all that said, let's dig in. External static pressure. Easiest way to look at it is what I have written here. The blood pressure of your HVAC system. And by the way, if you are here because somebody parachuted you in here, make sure you read the HVAC 101 chapter. It's the second chapter of my book, The Home Comfort Book. There will be a link below. And that compares the HVAC system in your car to the HVAC in your house. And your house comes up severely wanting and that's going to be related very strongly to the next video on what we call badass HVAC or nearly perfect HVAC. So make sure you check that out if you happen to get parachuted in here. All right, so blood pressure, very important. So the basic idea of this is inside a balloon. So if you have a balloon blown up, there is static pressure. So there's pressure inside, but it can't go anywhere because it's tied up. If you release the end of that balloon, balloon, balloon, whatever. If you release the end of that balloon, you get velocity pressure. There's a new word and you want velocity pressure. But the problem is if you have too much static pressure inside, the balloon pops. So in this case, if you're looking at it versus HVAC, it puts a whole bunch of back pressure on the fan motor and the fan motor will die very quickly, like in a year or two. And they're not cheap. They're at least $1,000 installed. But if you have too little static pressure, there's not enough pressure to flow the air. So there's a balance, not unlike blood pressure. So like I mentioned, if static pressure is too high, the system is going to die early. There's a whole bunch of different ways that static pressure can take them out. If it is too low, the system doesn't flow air to the rooms that you want to get it to. So it has to be somewhere in the middle. Here's what the numbers are. So it goes from 0.08 inches of water column to 0.5 inches of water column. So we've been talking about all sorts of weird metrics. Here's another one, and we have the Brits to thank for this one probably. And then we haven't changed the metrics. So who knows exactly what this is? It's probably Pascal's in the EU. But where you want to be is in this 0.08 to 0.5 inch range. And here we are down here. Inches WC is inches of water column. And just so you have an idea, Earth atmosphere, how much pressure we're in right now is 407 inches of water column, which is 14.7 pounds per square inch or one bar. So this isn't a great deal of pressure that we're talking about. But it is, I mean, this is like a very strong wind. It's quite a bit of pressure when you consider the difference that you're normally going to feel. And another important note is we have gotten away with as low as 0.04 inches of static pressure and still had flow. So we still had the velocity pressure happening. So 0.08 isn't a hard rule, but it's a generally accepted rule. Okay, so if we put more flow into a duct system, we get more static pressure. And it's a geometric thing. So you may be at 1,000 CFM cubic feet per minute, where you get to 0.5 inches of water column. So you're hitting where you want. But you might go to 700 and you go to 0.8 or 0.9. So it's a wall when you get to where your system won't flow anymore. So if you have too much pressure, again, you're going to get equipment breakdown. And curse here is most systems that I have tested and that I hear in my HVAC breath room testing land in the 0.8 to 1.5 inch. So three times what they're supposed to have. Most manufacturers stop even putting any kind of ratings on how much airflow that they will have. So more in the 0.8 to 1 inch range. So if you're at 1.5 inch, that's high blood pressure. That sucker is going to block. And I've seen failures pretty early. So and this brings up a really key thing. So we talk a lot about reducing the load in a house so that it can handle or it can be heated by a two or a three time heat pump, which is 24,000 or 36,000 BTUs. And if anybody from the EU is watching this, 36,000 BTUs is about 9.5 KW. So a lot of houses may need a four or a five ton heat pump to really do them well in a cold climate if they're leaky. But most duct systems just can't do that. So you're going to toast that HVAC system really quickly. Most duct systems can really only handle two or three tons, which is why we work hard to reduce the load of our advanced project homes into that range so that we can put a heat pump in and everything is honky-dory. Every ton of airflow is 400 cubic feet per minute. Give or take. It can be as low as 275, but that gets into a whole other thing. Like that'll make your air conditioner suck all kinds of moisture out of the air because the coil gets really cold. But that's beyond the scope of what we're talking about here. But in general, if you think 400 CFM per ton, that is kind of the standard. So two tons is 800. Three tons is 1,200 CFM. And very few systems as they stand can handle more than 1,200 and stay under half an inch of water column. So you have to be careful with that sort of thing. So there are three options to fix static pressure. So the first one is we reduce the heating load so that we can downsize the system. And I'm going to show you that more or less happening in a minute. But that is done with insulation and air sealing. That is building shell work, which we're going to be talking about insulation and air sealing after the HVAC section here. So that's the first option. You reduce how much it takes to heat the house. Second option is you make the ductwork bigger. That can be possible. And a lot of improvements can be made at the equipment or near equipment changes, as they're known as. But if you need to enlarge ductwork, particularly it goes up inside a wall or something like that, good luck. That's some pretty major surgery. But in general, what we find is if you downsize the systems, you right size the duct systems. So downsize the HVAC systems, right size the duct systems. So that oftentimes works. But you have to measure. You have to test. You have to know what you're doing. The third thing is you use resistance backup at low temperatures. So say you have a four ton load house, but you only have three tons of ductwork. You put a three ton in, and you use resistance to make up the difference in the very cold weather. It's a tool. And here we are, resistance backup, like I talked about the last time. If your ducts are too small, so you can't put the right size piece of equipment in, because the house is too leaky, you can use resistance to make up the difference. So you need to test this. And so now you'll see me, I'm going to use ESP abbreviated for external static pressure moving forward, because it doesn't fit on the slides very well. And you need to test to see what this is. It should be under half an inch when it's on high fan. And I want to note, so there's two different types of fan motors out there. So there's one called PSC. That's old school. Think of it like a giant football player that you can throw another guy on his back, and he just keeps going. You can give them high static pressure, and they flow less, but they don't care. They just kind of, you know, they go along, this is fine. I guess like that dog meme, sitting on a stool in a burning bar, this is fine. That's how PSC motors are. The new ones, ECMs, stands for electronically commutating motors. So ECM motor is technically electronically commutating motor-motor. But the ECMs are much more like a European soccer player, the supreme Adana, you touch them on the shoulder and they fall over, writhing in pain, pretending like there was a foul. So they're very efficient. They use a lot less power. So where a PSC will pull 500 to 1,000 watts all the time, no matter what you do to it, a ECM on low will pull as few as 15 watts so in low stage, in checking all of our systems, everyone has been between 15 and 40 watts on low, which is almost nothing. It's a couple bucks a month worth of electricity. What needs to happen though, and what it has happened is in July of 2019, every furnace was required to have an ECM motor put into it. So any high volume furnace. So basically anything that you as a normal consumer are gonna buy has an ECM motor now. And we're hearing of a number of failures already. So this only happened a year and a half ago as I'm recording this. And we're already getting failures after one or maybe two heating seasons because we're putting ECMs in a situation where they're not happy. So this is a real problem you're gonna hear about this more. And this is a known problem by the way, there's even a meme for it. So my friend and HVAC 2.0 contractor, Michael Housh put this meme together. So high static, peck man, nom nom nom nom. It's gonna eat them. These motors are solidly $1,000 each to replace. They may be more depending on your unit and your market. So this is something you want to avoid and there's other things that will go wrong in your system because of this as well. So hopefully I have put a little bit of the fear of God in you about static pressure because it's important. And now let's talk about testing it. I'm not gonna go super deep into this but I want you to have at least an idea of what's going on. So this is also from Michael Housh of House Home Energy in Monroe, Ohio. He's awesome. He is so awesome. What a good guy. And so he put this together and it shows where you drill holes so that you can test all of these things. So total external static pressure on a furnace is from before the fan, because the fan's in here, the heat exchanger's here and then you test after the heat exchanger. So you're testing before the fan and after the heat exchanger and the difference between those is your external static pressure. This is again, part of the HVAC 2.0 process. You're tired of me saying that but we built this to be friendly to electrification. So you wanna find one of these contractors or create one, which we will get to at the end of this course. All right, so I wanna show you some actual numbers. This is me testing one of our projects. So this is test in. This is a furnace. So this is the existing furnace that was there. It was about 20 years old and it was starting to make some weird noises. It was getting towards end of life. So note there is the red probe up here that this is actually before the heat exchanger. So this is weird for my market. It's actually a down flow. So it's blowing down. So this is the filter right here. This is testing after the filter and the other hose down here, which has a blue tip on it is after the heat exchanger and then the air conditioner coil is down here. So they're always in a line like this. So the static pressure, you can see there's 0.523 and then 0.2687 and even though this is negative, you look for the difference between them. So how far apart are they? So it's easier just to add them, ignore the whatever negative symbols in front of them, just add them together. So we are at 0.792 inches of water column. So this is well above the 0.5. This is an old PSC blower. It was probably fine, but this is not ideal. We can't run a modern ECM motor system with static that high without expecting some problems. So post install. So now this is a two ton heat pump and it's actually oversized for this house. The model didn't say it was. I wondered if it might be because it's a condo with a shared wall. It's oversized. I've watched the thing run. But now here we are again. Here's the red probe going in. So this is the big filter right here. So it's after the filter and you can see the blue probe in down here that is after the whole heat pump unit. So the heat pump has one fewer thing in it. There's no furnace in this. It's just a coil like your air conditioner and then a fan and note how much lower these numbers are. So if you add those two together, you get 0.235 inches of water column. So that's a super happy system. We're running at less than half of what the recommended high is. So this thing's crazy quiet. One of my favorite things to do on a project is once I'm done, I will go crank the thing to 100%. Go find the lady of the house who usually notices that the systems are noisy and say, so is it noisy at all? Do you notice the sound of it? And almost everyone says, oh, it's on? Yeah, it's at 100%. This is everything she's got. And they just kind of get wowed by that and you move on. That's partly delivered because of low static pressure. This is part of the magic. So this is something you need to be aware of and watch for as you are finding a contractor to do an electrification. So if they try to jam a large heat pump in there, you're gonna regret it. It's gonna create some problems. So be very careful. Now, a couple of things to note on doing this testing. This is a Blower Door Monometer. This is an older one. I bought this back in, oh, nine or 10. So it's 10 years old. But these monometers, to be accurate enough to do this, they start at 400 bucks. New version of this for the Blower Door is 1500 bucks. This is not something that you really wanna do yourself because it requires this accurate tool. You also need to drill a bunch of holes into your system. And particularly when you're drilling near the coil or the heat exchanger, bad things can happen. So you can release the refrigerant, which is not something you want inside your house. You could drill a hole in the heat exchanger and cause a carbon monoxide risk in your house. So this is a professional job, important note. So I will tell you stuff that's DIYable. Heat pump, water heater. If you're advanced, go DIY that sucker. But this, be careful. It still makes me nervous when I do it because I'm not a tech. And remember how I said you're gonna get tired of hearing about HVAC 2.0, the comfort consult brought this up a number of times in the past and we're gonna keep bringing it up because it's a solid process that helps reduce all kinds of risks and increase the odds of success of whatever project you're doing, but particularly electrifications. So guess what else is in the comfort consult? You betcha, static pressure testing. So it's not always in there. We don't require it, but it is part of it. And generally we listen to the system because oftentimes the oil can. You'll turn the air handler on and you'll hear and you'll watch the ductwork actually expand with the high pressure in them. If that's the case, it's like, well, let me go get my drill, we're gonna test this. It only takes 10 or 15 minutes to run this test, so it's not a huge deal, but the comfort consult's already pretty long. It's three or four hours as it is. So, but it's an important thing to ask about, particularly in electrification. Now, I want to go back to the large filters. See how big this filter is up here? So A, it's four inches thick and B, it's actually larger than the unit itself. Normally we size the ducts to be exactly the same size of the filter and it's actually pretty close. It's about the same size as the actual filter hole that's inside here. But the duct modifications that happened here and pretty small duct modifications mixed with the lower airflow from a small heat pump that is right size to the house. And we did some air sealing on this house as well. The relatively minor, I think we got a 20 or 25% drop and most of my drops are upwards of 50%. But by running this nice big filter, which has very low pressure going across it and running a nice large duct and downsizing the unit, we didn't change anything else in this house. One small addition, there's a little duct that's behind here going to the bedrooms behind this space. But this led to about a two thirds drop in static pressure with the same duct system. So this can be done. You can right size the system to the duct system. So that's an important thing to know. And by the way, that filter, so this is a little bit different configuration but we call this bad ass HVAC and this is coming up next. The consumer friendly version of this is nearly perfect HVAC because it is. So this tackles all sorts of stuff. You've got this nice filter in there. And so this is all in one line rather than being a U shaped system like this one is, but this is a traditional basement system in our market. So this tackles the six functions of HVAC, which is load matching. You want to have variable speed and throttle for it. You want to have filtration, which is the nice media filter. You want to have dehumidification, which can be done with a reheat dehumidification with that resistance backup that I was talking about last time. A fresh air line. So there's a fresh air duct that goes outside with a damper on it that closes when it gets too hot or cold. Mixing, you want to stir the house all the time and run that air through that filter, particularly as we are in the pandemic. One of the best things you can do is filter the air in your house frequently. That's true all the time. If you want to get sick less, filter your air a lot and have a really good filter. So it actually knocks the garbage out. And then the last one is humidification, which isn't appropriate for all markets or all houses, but it can be nice to not have super dry skin. So we're going to be talking about this in the next video. That's the short version right there. All right, last little piece we're going to talk about for important details is surge protection. So many power systems have a lot of voltage fluctuation. So you may hear a traditional power called 110. You may hear it called 120. They're both technically correct. So they're allowed to be somewhere between 110 and 125. But if you get lots of fluctuations, the inverter equipment, which is what you want to buy, is very sensitive to that. You will fry compressors. Ask me how I know this. So we have lost a few because I didn't know about this. Now I know about this. So this is the one that is the industry consensus. It has five different circuits in it. So it'll handle five different major surges without killing your equipment. It's not inexpensive. This is a $500 part plus install. And you can get some cheap whole home ones for 100 bucks or 150 bucks for the part. They may be fine. I don't know. But when you ask a whole bunch of really good HVAC techs, what do they like and they all say this product, you just shut up and recommend that product. So here we are, ICM 493 Surge Protector. This goes outside right along with your shutoff that is on the outdoor unit. And here's what power fluctuation looks like, by the way. I pulled this out of the Sense Energy Monitor Facebook Group. And see how he's got 120 on one side and almost 120 and 109 on the other. That's a big difference. And it was 84 times in the last month. So this is one of the beta things that Sense has running right now. They call it labs. This house is really problematic. If this fellow had an inverter heat pump, he probably would have toasted some equipment. So you get a lightning strike where there's all kinds of things that can lead to a surge. Spend the money, put this in. It's just a good idea because power fluctuations kill inverter compressors. They can also kill the boards on the inside unit. All right, so that's that important HVAC details. So we talked about resistance heat last time. Again, how it is a tool. We touched on it again here. Static pressure is the blood pressure in your house or in your duct system rather, should be between 0.08 and 0.5 inches of water column. And then surge protection. So these are all important pieces and this is in the weeds, but you're early adopters. So if you don't know about this and you don't ask about this, the odds of you having failures related to these things are really hot. And that is what we are trying to avoid. And again, you're gonna wanna try and look for an HVAC 2.0 contractor or find someone who's willing to go with you through the process and become a 2.0 contractor. We're going to help make that very easy. All right, and that's the end of this module. So that's it. This piece of the electrify everything course. Again, if you happen to parachute in here because somebody sent you the link, please sign up for this because you're missing a ton of other stuff. So I'm probably stupid for putting all this out there for free, but I will also put a link to buy me a beer under here. So if you have gotten value from this course and the other pieces, send me some money. So you can send me five bucks. You can send me a thousand, whatever works, whatever value you find in this, that would be nice because we are doing all of this on a shoe strength. So we are building HVAC 2.0 on our own dime, which means we are not making any money off of it yet. It has some cash flow, but it's not making money yet because we are working to build it and build it really, really well so that when we do step on the gas, it doesn't break. We don't want to scale a turd. So if you enjoy our work and this course, send us a couple bucks. And then also sign up for the rest of the electrify everything course, which is free. So thanks again for watching this. I'm Nate Adams, sometimes known as Nate the House Whisperer and I'll see you next time when we get to talk about badass HVAC. It's actually going to be a webinar. So enjoy your day. See you next time. Bye-bye.