What type of insulation for a house in Garden Grove CA?

[Natosha Jacobs]

My sister is building a new house in Garden Grove CA. The golden opportunity to do it right - she wants to have the best possible insulation for the walls to keep the energy bills low and to have the comfort. Please advice. Many thanks.

 

[Greenman]

My sister is building a new house in Garden Grove CA. The golden opportunity to do it right - she wants to have the best possible insulation for the walls to keep the energy bills low and to have the comfort. Please advice. Many thanks.

It's not just wall insulation. It starts with how the house is constructed, the number type and placement of windows, the type of roof. That should all be nailed down as well. If she's just looking for the best insulation without specialized construction, spray foam is the way to go.
She will also have to look at the mechanical systems, how the house is heated and cooled. Note that most of this will have been addressed in the Title 24 package that's part of the plans.

 

[deadlyapp]

Greenman basically covered it. I think the best insulation I'm seeing that is used in LEED certified buildings is rigid or spray foam. The rigid foam you can get about R5 out of less than an inch of thickness, compared to standard fiberglass batts which I think are R13 or so for a 2x4 wall. You can also easily add additional rigid panels on the exterior or interior walls to improve it.

For ceiling insulation, spray in seems to work well and is certainly one of the easiest ways. Since any new homes in California have to have solar IIRC you'll greatly help the overall heat load on the roof.

But remember that insulation isn't the end all for improving the envelope. Make sure the builders do a good job sealing windows, doors, etc. You'd be surprised how much you can leak in those areas. Similarly make sure you're using high quality windows with low e coatings.

 

[Greenman]

I believe every new home in CA requires a blower door and duct leakage test. Though I could be mistaken, I don't build new homes.

 

[Fallen Kell]

Well, there are a lot of things, insulation is just a small part of it. You want to be talking about passive house standards. You need to use something like Zip-R home sheathing (or similar), and absolutely need to make sure the home is properly sealed for air tightness (using something like Aerobarrier). I can't stress this enough, but building to "code" just won't cut it if you actually want proper insulation. You really need to be looking at double code for insulation R values, and about 10-20x code for air tightness.

See these videos for some info:

You really need to have a builder that uses these systems, you can't just have a builder just install these systems and expect them to do it right. In fact, using these systems and doing it wrong will produce more problems faster than a more traditional setup. As stated in the videos, these things affect many other things in the home, such as having your HVAC having proper external air supply, with humidifiers and dehumidifiers and filtration.

 

[Greenman]

Depends on where you live. In a climate like Socal the temperature delta is so small that the ROI of doubling insulation is near zero. In North Dakota it's a different story.

 

[deadlyapp]

Depends on where you live. In a climate like Socal the temperature delta is so small that the ROI of doubling insulation is near zero. In North Dakota it's a different story.

Yeah in Garden Grove you've got a bit warmer temps than the coastal cities, but generally pretty temperate breezes that keeps the temps in the 80's or so at the worst parts of the summer. Maybe a handful of days in the 90's +

Shit I never had AC when I lived in LA area, but I was always in a beach city.

 

[Fallen Kell]

Depends on where you live. In a climate like Socal the temperature delta is so small that the ROI of doubling insulation is near zero. In North Dakota it's a different story.

Sort of, remember proper insulation works both ways for both keeping heat in during the winter and keeping heat out and cold air in during the summer. There are places where this doesn't help as much, but if you see 90+ or 100+ degree temps in the summer and 40 or lower in the winter, you would be astounished how much energy savings adds up over the lifetime of the home. And remember, this kind of investment really is a lifetime investment if done properly. Done poorly and you will be ripping it out in 2-3 years due to water damage and mold.

 

[Greenman]

Sort of, remember proper insulation works both ways for both keeping heat in during the winter and keeping heat out and cold air in during the summer. There are places where this doesn't help as much, but if you see 90+ or 100+ degree temps in the summer and 40 or lower in the winter, you would be astounished how much energy savings adds up over the lifetime of the home. And remember, this kind of investment really is a lifetime investment if done properly. Done poorly and you will be ripping it out in 2-3 years due to water damage and mold.

I know a little bit about it, I'm a general contractor.

 

[Scarpozzi]

My biggest concerns with spray foam are that foam does compress a deteriorate over time. Additionally, in roof applications, it can limit airflow because it results in a solid cavity unless you install air foils to all air to circulate next to the roof. That being said, all products have potential to lose effectiveness over time.

I'm a huge fan of cellulose insulation based on cost, fire retardation, and R-factor. For the underside of roofs, look into radiant barriers if you have an insulated ceiling and a non-insulated rafter/attic space. It can basically reflect the heat off the top side of your insulation and help reduce the temp differentials. If you've ever worked under an uninsulated roof, you'll understand how much that can help.

 

[Greenman]

My biggest concerns with spray foam are that foam does compress a deteriorate over time. Additionally, in roof applications, it can limit airflow because it results in a solid cavity unless you install air foils to all air to circulate next to the roof. That being said, all products have potential to lose effectiveness over time.

I'm a huge fan of cellulose insulation based on cost, fire retardation, and R-factor. For the underside of roofs, look into radiant barriers if you have an insulated ceiling and a non-insulated rafter/attic space. It can basically reflect the heat off the top side of your insulation and help reduce the temp differentials. If you've ever worked under an uninsulated roof, you'll understand how much that can help.

Around here we foam vaulted ceilings to avoid the need for ventilation. Or like the place I'm currently building, the cavity isn't deep enough for the required R value.

 

[Fallen Kell]

Personally I have come to really like Rockwool for most insulation. You still need some foam in places, but Rockwool solves so many other issues (insect resistance, fire resistance, and mold resistance).

 

[Scarpozzi]

Around here we foam vaulted ceilings to avoid the need for ventilation. Or like the place I'm currently building, the cavity isn't deep enough for the required R value.

I only did spray foam in a vaulted stairwell that was framed with 2X6's and in my garage ceiling with closed cell as a vapor barrier/temp break below my bonus room. I always figured opening those doors for even 1-2 minutes lets a large amount of cold air in that doesn't easily warm up or escape.

I installed pex loops in the concrete years ago with a plan to use solar/radiant heat to warm the floor on colder days/evenings, but never invested in a heat exchanger/tanks/pumps/etc to build it out. I may, I may not....but at least the pex is in there if I want to.