Subfloor insulation in a vented crawlspace
HIJINX
| Posted in Energy Efficiency and Durability on
Hello I live in Los Angeles, Inglewood to be precise. Our house was built in 1940 and had a gas furnace. We are in the process of putting in a new heat pump but my wife insists we insulate the subfloor. I have received so much contradictory info about this. Our goal is a simple affordable solution. Should we encapsulate? Vapor Barrier on the floor? Air Seal? R19-R30 fiberglass between the joists? Should it stay ventilated or should we seal the crawlspace? The ground is dry dirt and it’s not wet. Any help would be very appreciated!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
HIJINX,
You may find these articles useful:
https://www.greenbuildingadvisor.com/article/should-you-encapsulate-your-crawlspace
https://www.greenbuildingadvisor.com/article/building-an-unvented-crawl-space
If there is mechanical equipment in the crawl space, I would be inclined to make the space part of the home. This would require sealing the crawl space vents, adding a vapor retarder to the crawl space floor (sealed to the foundation walls), adding insulation to the interior foundation walls, and conditioning the space using either the existing heating/cooling system or by adding a small dedicated system that only serves the crawl space (seeing as you are in Los Angeles, you may not need a dedicated system, your climate is pretty mild). You may also need a dehumidifier in the space. Unless you are in the space often, I recommend monitoring conditions in the space, especially humidity. A wireless weather station could work, place the sensor that is normally outside in the crawl space.
Your states energy code will dictate the minimum amount of insulation you will want to go for: https://codes.iccsafe.org/content/IECC2021P3/chapter-4-re-residential-energy-efficiency