Image Credit: Martin Holladay Photo 2: Pretty — but ineffective — flex ducts in a 10,000-square-foot home. The homeowners complain of the bathroom being too cold in summer and the bedroom being too warm in the master suite served by these ducts.
Image Credit: Energy Vanguard Photo 3: Mr. Deep Deshpande, is standing in the home he's having built. The Wall Street Journal reported that many home buyers like him are getting their own construction loans to build million-dollar homes, but most don't understand the inadequacies of the HVAC systems they have installed.
Image Credit: Bob O'Connor - Wall Street Journal Photo 4: Panned rafters for return air in a million-dollar home. Little insulation and no sealing mean this home may pay extra, in dollars and comfort.
Image Credit: Jamie Clark, Climate Control, Lexington, Kentucky Photo 5: Atmospheric combustion furnace in the basement. Yes, it's legal, but it will make the building enclosure more difficult to seal. Besides, expensive homes should have sealed-combustion appliances.
Image Credit: Energy Vanguard
I wonder about a lot of things. I wonder what life would be like if gravity were stronger. I wonder why Americans don’t dance more. I wonder why so many people who can afford million-dollar homes get cheapo HVAC systems. That last one bugs me more more than the first two, by the way. It weighs on my mind because cheapo HVAC seems so out of step with the rest of a million-dollar home.
Certainly, some expensive homes get HVAC systems appropriate to their class, but I’ve seen and heard of so many contrary examples that homes with high-quality HVAC are probably in the minority. Here are five examples I’ve seen, either in person, in the media, or through others in our field.
Exhibit 1: Ductopus in a $3.4-million home
Martin Holladay, the Energy Nerd here at GBA, came to Georgia earlier this year, so I took him to see the green community, Serenbe. On our way back, I drove him by the Atlanta White House, and it just so happened that the house across the street, built by the same home builder, was having an open house. It was built for $3.4 million, one of the real estate agents said, but was listed at a mere $2.49 million. What a deal!
After exploring the lavish finishes upstairs, we discovered two mechanical rooms in the basement and the ductopus above is from the first one. The other had a ductopus, too, but not quite as impressive as this one. (And yes, that’s 6 mil poly on the basement walls. In Atlanta. They put it on the attic-side of kneewalls in the two bonus rooms, too.)
Exhibit 2: Pretty — but ineffective — flex ducts in a 10,000-square-foot home
In photo 2 below, you can see a mass of flex duct that one person on the Energy Vanguard Facebook page compared to the CERN particle accelerator. Yeah, the installers made it look pretty, but guess what — those ducts all go to the master suite, which is one of the least comfortable areas in the house.
The master bath gets too hot in winter and too cold in summer (i.e., too much air). The master bedroom gets too hot in summer and too cold in winter (i.e., not enough air). They should have designed and commissioned the system properly. A good design probably would have specified trunklines instead of all those individual ducts, and the air flow would have been much better.
Exhibit 3: Crappy flex install in a spray-foamed home
In photo 3 below, the proud fellow, Deep Deshpande, is standing in the home he’s having built. It’s his dream home in Brookline, Massachusetts. The Wall Street Journal recently published an article about affluent home buyers getting their own jumbo construction loans to do just as Mr. Deshpande has done. Usually, they hire a home builder to build the home, but if you look at that photo, you’ll see a mistake that’s common even in million-dollar homes.
See all that flex duct? That’s Walmart-style. Wait, I think I’m being too generous. It’s probably more like Big Lots or Dollar General-style.
I can’t see much of the duct system in that photo, but I can see enough to tell me that they may well end up with comfort problems.
- The bundle of flex duct behind Mr. Deshpande is strapped a little tightly.
- If they’re running three ducts in the same direction, why didn’t they use a trunkline?
- Worst of all, they ran flex duct in the roofline.
It’s a shame that they’ve done this, too, because they used spray foam insulation in the walls and roofline. Someone obviously cared a bit about making the house comfortable and efficient, but as usual, that didn’t apply to the duct system.
Exhibit 4: Panned rafter return ducts
This one blows my mind. They’re using a pair of rafter cavities in a vaulted ceiling as a return duct in this 9,000-square-foot, $1.5-million-dollar home in Kentucky. The building code, at least in some areas, does allow you to use building cavities for return air, but running that return air right next to the roof deck is just stupid. That little bit of bubble wrap isn’t going to help a lot, and there’s no evidence of any sealing there either.
The real mind-blowing part, though, is that PVC pipe running through “duct.” At first, I thought maybe it was going to be part of the condensate line, but Jamie Clark, who sent me the photo, told me it’s part of the attic ventilation system. Notice that there’s another one in one of the bays to the right. Hmmmm. I wonder how effective that will be at moving air from soffit vents to the ridge vent.
Exhibit 5: Atmospheric combustion inside the building enclosure
See that furnace in photo 5? If you know anything about HVAC systems, you’ll recognize immediately that the furnace you’re looking at is a standard efficiency (80%), atmospheric combustion model. (In case you’re wondering, the flue was intentionally disconnected and won’t be left this way.) The problem here is that it’s in a million-dollar house with a million-dollar view on a beautiful lake. Why would anyone do this?
In addition to an atmospheric combustion, low-efficiency furnace just not fitting in, there’s also the problem of it being an atmospheric combustion furnace. They’ve put it in a mechanical room in the basement in this house, which means that room will have to be isolated from the rest of the house, and that probably wasn’t done well when they finished the house. Code also requires two big holes in the house to bring combustion air into that room. (Read more about the problems of atmospheric combustion inside the house.) The home in Exhibit 2 above also had 80% furnaces and natural draft water heaters in the basement.
Why do so many expensive homes get Walmart-class HVAC?
Sadly, this problem is all too common. The big expensive homes always get the fancy finishes. They often get the hot, green products as well: spray foam insulation, tankless water heaters, ground-source (a.k.a. geothermal) heat pumps… If they’re putting in a forced-air HVAC system, though, they usually get crap for a distribution system.
Whose fault is this? It’s hard to say in general, but here’s a list of some of the main culprits:
- HVAC contractor. They did the work, so they have to bear at least some of the responsibility. Still, good ones will walk away from jobs where they think they’ll have to compromise too much, leaving that work to the companies that don’t know how or don’t care to install high-quality HVAC systems.
- Home builder. They hire the HVAC contractor to fit the budget. A cheapo budget gets cheapo HVAC, so they need to adjust their budgets for HVAC.
- Architect. Million-dollar homes usually have architects, who often have little understanding of the importance of HVAC. I spoke earlier this year with an architect who’s done work on expensive homes, and he said they rarely include HVAC as part of their design because it’s too hard to sell the client on it.
- Homeowner / buyer. For many, the obsession with granite countertops, or whatever the latest finish fad is, dooms the HVAC system to Walmart-class. This applies to spec homes as well as those built on contract. Mostly, though, it’s because they don’t understand how much more comfortable a home with high-class HVAC can be.
In the ideal case, all of these parties work together as a team, along with the HVAC designer and the other trades whose work affects the performance of the home. I know that not a single home is ever built to the ideal case, but we could certainly do a lot better.
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