Hi All,
I’ve got a 1950s single story house in Southern CA/San Fernando Valley. My attic has a barely visible minimum of some old blown in insulation. With the temps here ranging from 40 to 110, it’s a cold drafty house in winter and hot in the summer. Given the limited space, wiring, a few recessed light cans, etc., I’m looking for guidance on ways to improve the insulating performance. As a DIYer, I’m not sure if this is something I want to tackle, but there doesn’t seem to be many visible insulating subs in this area. Should I be laying down fiberglass or renting a blower and buying cellulose from Lowes? Given the probable similar poor insulation in the walls, is working on the attic even advisable? Should I worry more about old windows and doors? Thanks.
Replies
The insulation is great for keeping your house warm in winter, but its a killer in summer.
If you fill the attic with insulation, it will be cool during the day and hot from 5:00 pm to 10:00PM. When the temperature is over 100 degrees there, the insulation does not stop the heat - it slows its travel and will actually hold its heat. The insulation will make your house hotter in the evening even when the sun sets when you are trying to go to sleep. The large warehouses in you area use reflective foil, it keeps the heat out without storing it, but its reflective properties may reduce the life of our roof.
You may find that the old original windows are to blame for it feeling cold in winter.
Thanks,
I have a vent fan that we run in the summer to move the hot air. I've seen that reflective foil at the bigbox. I just could quite imagine putting 2000 sq ft of it up in the confines of my attic.
Attic insulation will very definitely help keep the house cooler. On a hot summer afternoon when the temperature in my house is up around 85, if I go out in the garage, under the same roof but with no ceiling insulation, it's much hotter.
It's true that in the evening when the outside temperature goes down, there's some period of time when the insulated ceiling is warmer than it would be without insulation, but it's also true that I can open the windows in the evening and get that cooler air moving through the house. Better attic venting and a whole house fan would both be helpful, but even without them, there are seldom more than two weeks during the summer when the house is unpleasantly warm at bedtime.
Toad, there are a number of things you can do to both increase comfort and reduce your bills. I know crawling around in the attic to staple up a radiant barrier does not look like fun, but if you do it while it's cool, it may not be too difficult. The summer payoff will be good. After the barrier is up, and some form of ventilation to pull out the hot air, move on to sealing attic to conditioned air leaks, duct leaks,etc.
Finish in the attic with blown cellulose, BUT, be sure not to cover the recessed light cans unless positive they are IC rated. Also, I would look for leaks at your access to the attic, and around a house exhaust fan.
You may improve your costs by 30% with just attic centered work.
From what you describe, you have the typical '50's house, losing heat in the winter, and gaining heat/humidity in the summer through your attic.
Windows, leaking weather stripping and other penetrations are also correctable. Hope this is helpful, Paul