Derek Cole breaks down A/C options for new homes, ranking geothermal as most efficient, then mini-splits and heat pumps. New duct systems leak about 10% of air by default, so he recommends aerosol sealing and metal ducts over fiberglass, plus ventilation systems like ERVs to handle off-gassing from new materials.
Questions this episode answers
Episode 81
2019-09-05
10% leakage
Chapters
Hey, on this episode we talk about what do you need for your new home? And why do I need to seal my new duct system? You ask your comfort and energy questions and they get answered. This is the Ask Derrick Cole Show. Hey everyone, this is Derrick Cole. Welcome to episode 81 of the Ask Derek Cole show. Answering our home and energy questions.
I'm building a new house. What kind of air conditioning should I have?
That's a common and good question. It kind of depends on what you're building and what you're looking for. Now the most efficient way to go would be, in my opinion, geothermal. If you're building a new house and you have, you know, you don't have grass yet, it's obviously easier to do the wells and to do the loops and not cause any problems. And you can, with all of these, you can fold them into your house payment and becomes a lot better for you. So geothermal is really what I would recommend to start with. But it kind of, I mean you can go geothermal, you can go multi zone mini split, you can go traditional heat pump, you can go dual fuel. I mean there's, there's so many options. And really, Steve, my father has really said it the best. You know, if you, if you give me a target, I can hit it versus having this shotgun approach, right? I mean, what's in your budget? First of all, if it's in your budget to go high end and go really efficient, let's do it. If it's in your budget to go standard, basic, let's just get done, bare bones, minimum, then we can do that. But then again, you know, when you give us your budget, then we can see what you want, see what the budget is and then fit something into that mold. It's kind of obviously harder to go with the shotgun approach which was, you know, give me the most efficient. Alright, we're gonna give you the most efficient. I know my budgets right here. Okay, well let's come down to right here. But if we started with that, that would have been a little easier because then we wouldn't waste your time. When to waste our time. We could just talk a number. So I was talking to somebody recently and they said, you know, this number is like 10% of my home budget. I said, well, you're dealing with an appliance that's half of your energy use every single month. So I've said it before, heating in there, you either pay for it now.
Or pay for it later, but eventually.
Going to pay for it. And some people say, what do you mean by that? Well, if you pay up front and you get a super efficient unit or an efficient install, then you'll save money. If you go with the cheaper unit or the low end equipment or the value based brand, then you'll pay for every month in energy bills. So that's what I mean by hitting error is one of those you don't pay for it now or pay for later, you'll pay for upfront, in this case up front and put it in your house payment and save money every month on lower energy bills or pay for it later by going low end to start with and then having higher energy bills every month. So I guess to answer the question, I haven't answered the question. It depends on your budget and what you're looking for. Now we have some homeowners who like to keep the house at 75, 78 degrees. And then we have some homeowners that want to keep it at 65, 70 degrees. Well, obviously in that situation, geothermal would be better than traditional heat pump. But it depends on your home, your choice, what you want to see, what kind of energy bills you like to see. I mean you can go with radiant barrier in the attic, save some money. That way you can seal the crawl space, you can have a dehumidifier in the crawl space, seal it up, you can go that way. That will be efficient, the radiant barrier will be efficient. But then again, it goes back to your budget. What can you look at? What are you looking at? What are you looking to purchase and afford? Some people have built a really tight home. You, in that case, you need, well, in all cases really, but in that case particularly, you need an ERV energy recovery ventilator. Because you have such a tight home, you have new carpet, you have new countertops, you have new cabinets, you have new paint, all this stuff off, gases, chemicals. So when you have a really tight home, there is nowhere for that to.
Go except for your lungs. So ERV actually exchanges outdoor air conditioned. It will condition it and takes out the bad air, brings in the good air. Also you need to look at air cleaning products on top of that because with a newer home, homes today are not built the way they're built in the 60s and 70s. Whereas a breathable home, where they weren't too worried about the insulation or the paneling or, you know, energy was cheap, it's not that way today. So now you need to, yes, you can build a tight home, but you need to make it efficient and healthy as well. So in that case you need an ERV and need some air cleaning to go along with it. So that was a long way to say it depends on your budget.
And you made it long.
You see what I'm saying, though? It was build these really tight homes, which is great for energy, but it's not so great for health because now you're breathing all the stuff in. There's nowhere for it to go.
Why do I need to seal my new duct system?
Anytime in this state, you install a new duct system, you have to do. And Caroline knows this because she's now doing permits. You have to do what's called a duct test or a duct blaster, as we call it. You have to measure how much leakage is in that new duct system. And there is a point, depending on the city of the municipality as to what they want to see. 5, 10% of leakage that they want. So let's go with the round number. Let's see. It's 10% leakage. So you're leaking 10% of the energy you're paying for out of that new duct system. So if you seal it, it can get down to zero, right? So if you get to zero, that's obviously more efficient than losing 10, right? So that is why you want to seal the new duct system. Now, in this area, we see a lot of duct board, fiberglass duct system. Again, that is bad for your lungs, bad for your health. So we go back and we install metal duct. That way you're not breathing in the fiberglass any longer. The downside to installing that metal duct is that you have joints. And no matter how much you try to seal it manually on the way there, you seal it, seal the joints on the outside with mastic, you seal it up with tape, you seal it up with insulation. You seal that up on top of the mastic and tape, still you're at 10% leakage. Because there is no way a human being can actually seal all the places that air flows. Now, with dove sealing with air seal, it works on pressure. There is not. It's an aerosol. There's not a human being, you know, putting mastic and painting it on the joints. No, it's a machine. It's all controlled by this aerosol, aerosol spray. It's working on pressure and it's filling the holes as it finds the leaks. So that is the most efficient way to do it. If you're okay with 10% leakage and wasting 10% of your energy bill, that's cool. Just keep doing it. But most people are not so I would recommend after that duct test to make a decision. You know, if you got a 2 ton system and you're leaking 4, 3%, you know, if you're fine with that, that's fine. But if you got like a 3, 4, 5 ton system and you're leaking 10%, that adds up to be quite.
A bit of money.
So that is why you need to.
Sell a new duct system now. Duct board, fiberglass duct that is. There is less leakage in that than a metal duct. But there's always a give and take. You're breathing in the fiberglass, which is not good. Some people, some companies still use fiberglass again. Once fiberglass is airborne and gets in your lungs, there is no way it's ever coming back out. So. So we don't install that anymore. We go with metal. It's a lot cleaner, a lot better install. And once you seal it, it's a no brainer really. I mean, you're not breathing in the fiberglass. You're stopping the dust and the dirt from coming into the duct system. Because now it's sealed. So you don't have to deal with duct cleaning any longer. Unless.
Let me back up a little bit. Unless you have that kid and you have the grills on the floor and tell him to sweep the floor and he sweeps it into the grill. Then you might have some duct cleaning in the future. I don't know of any kid that does that. Maybe I used to, I don't know. You see a hole there and you just want to sweep it up because that's what mom told you to do. Sweep the floor. So to answer the question, that's why you want to see if your duck says them. So the perfect, the perfect thing would be like geothermal new install new metal duct system and seal it with the erv with the air cleaning. You got the best of all worlds together. You're like, oh, I'm so great. I'm so healthy. Such a nice house. So energy efficient. Everybody lives in Utopia. Not Zootopia. Utopia. Anyway, that's episode 81 of the Ask Derek Cole show. Be sure to ask your questions and we'll get them on the show.
