Redeeming a modular home
If you were to get a new modular home, with code minimum insulation and dubious quality air sealing, what could you do to improve its energy efficiency? (Zone 5, Rochester, NY Area.)
–John
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
I have a modular home that was built in 2004. My initial blower door test showed 1.91 ach50, after air sealing various penetrations we were at 1.0 ach50 on our last test. We've since sealed the dryer vent and the hole & conduit from the meter to the electrical panel, and I'm planning to seal between the basement slab and the foundation walls soon. (yes, that crack around my basement was a large air leak. o_O)
We when had some drywall down for a reno we found that the insulation had been really well placed in the walls. We obviously didn't see everywhere in the walls, but everything I've seen points to this manufacturer doing a great job of mostly code minimum.
So far we've added insulation to the attic, had minisplits installed, and we had the foundation made with ICF when we were specing the house. The house was built with advanced framing which was a small step, but you might be able to talk to your dealer about double stud walls. Ours has a vapour barrier on the inside of the drywall, and thus has to dry to the outside, so I'm hesitant about adding rigid insulation to the outside and having a wall assembly can't dry to either direction. All in all though, it's still a stick framed house. The same things can be done to a modular home as a site built home. I don't have any regrets from buying a modular home and recommend them often.
What brand is your modular home, out of curiosity?
Thanks,
John
John,
Calum gave you good advice. Researchers have found that modular homes (for example, double-wides) usually have major air leakage problems at the seams where the modular units come together, so blower-door-directed air sealing would be at the top of my list for suggested improvements.
If this is a new home, plan to be on the site when the modular units are installed, and come up with an air sealing plan. You don't want to allow the siding to get patched unless you are there watching.
Mine was made by a Canadian company called Kent.