Proper Attic Insulation and Ventilation
LESLIE: David in Oregon is on the line with an insulation question. Tell us about it.
DAVID: Hi. I have a 1957-model house and it’s a ranch style. And we noticed this winter, when we had a little bit of snow, well, our snow left before all of our neighbors’ did. And we live in – around Salem, Oregon there in a valley, so it’s pretty mild winters and not too bad in the summer. I’ve got a half-a-dozen vents up on the – up there on the top of the roof. And those have been blocked off and there’s a fan – an exhaust fan – been put in there that’s on a thermostat.
DAVID: I want to know if I need to take those out, open those back up, turn the fan off and about how much insulation I need to put in. I think about 9 inches or a foot?
LESLIE: Well and you say you have 9 inches or a foot right now?
DAVID: It doesn’t have – it has like maybe three right now.
TOM: You know what, Leslie? It sounds like nothing he has is working correctly.
LESLIE: Is the right thing.
TOM: Or was installed right. That’s right, exactly. So …
LESLIE: Generally, with insulation, regardless of where you are in the country, you want anywhere between 19 and 22 inches and that depends on if you use the fiberglass batt or the blown-in. But that’s how much you need, whether you live in a hot climate or a cold climate, just to keep your home operating efficiently and keep the temperatures the way they’re supposed to be inside.
Now, with your venting, you really need a continuous ridge vent and you need soffit vents. Because with insulation, you need ventilation to make sure that it works properly. So those are really the ideal situations. And a lot of times what happens is you may have a soffit vent but you’ve put insulation right over it or if you stored things – and you can’t even get the airflow in there. So if you have soffit vents, you need to expose them and allow them to do their job.
And exhaust fans are never a good idea.
TOM: Yeah, that’s right because they depressurize the attic space and they actually reach down into the house and they’ll steal air-conditioned air. So we say get rid of the exhaust fan, get in continuous ridge vents, continuous soffit vents. Add that 19 to 22 inches of fiberglass insulation and finally, you will have an energy-efficient attic and that’s going to really impact both your heating and your cooling bills in a very positive way.
DAVID: OK. That sounds like a good idea and I really enjoy you guys’ show. I listen to you every weekend.
LESLIE: Alright. Thanks so much for stopping by The Money Pit.