Add more Insulation or no?

[jmc13]

I thought I would throw this out there in hopes someone has actually done this, and if it really helps specifically in a desert climate.

I have a 2 story house built in 2000, 2500 sq ft with 29 windows, most face south/south west. When we toured the house before buying it was 100 degrees outside and thermostat was set to 72. The house was great until you walked in the master, which was at least 10 degrees hotter with two 10 month old air conditioners. We purchased the house and replaced all of the windows, and patio door, the master became 5 degrees off. We added solar screens, now the bedroom is only 2 degrees off. The master is 1/3 of the upstairs, with vaulted ceilings and every single day it fluctuates 10 degrees, while the rest of the house only changes 2-4. If we keep the door closed, the Master is freezing or roasting but the rest of the house isn't really effected. We had an energy assessment by the power company and were told we were missing insulation in a small spot in the attic (not over master), and it was almost below code in some other spots, the rest was fine. No real numbers just " about 6-8 inches up there", which if I'm not mistaken is less than the requirements of R30-60, so not fine. They don't offer any incentives, so it's 100% out of pocket. The walls on super hot days aren't hot, so the last thing I can think of is attic insulation.

With all of that being said I live in zone 3 close to zone 2. On days where it's over 105, or below 50 degrees the house struggles, especially our bedroom. I get it's lava hot out most of the time, so it's the nature of the beast and I get there is a diminishing return if you go overboard. However, has anyone added insulation, if so from what r-value to final? Did it actually provide a noticeable difference? Is it more summer or winter you notice a change? Any information would be great, real numbers would be great too. I can only get estimates of 10-20% from energystar.gov, and most online posts elsewhere are for super cold climates.

 

[needsajet]

I'm in the middle of this myself at the moment although not for heat atm. I really feel for you all over there in that crazy heatwave.

Just in case, I'll mention the aircon filters. Keep those clean to get the most out of your cooling. Dirty filters can stop it in its tracks.

I needed to decide how much insulation to add and found this article to be an awesome resource. The main thing is to ensure the insulation coverage is good, and that adding excessive amounts may lead to disappointment. In other words, make sure what you have is fully covering the gyprock. That's the biggest gain.

The Diminishing Returns of Adding Insulation - GreenBuildingAdvisor

If you're building a house and want to have a really good building enclosure, you need it to be airtight, handle moisture properly, and have a good amount of insulation. Ideally, you'd also consider the effects of solar radiation on the home, but for now let's just focus on the insulation. What...

www.greenbuildingadvisor.com

Over the years, tradies doing stuff up there had seriously messed up our insulation, carelessly chucking it out of the way and not replacing it. Fixing that up is a great gain.

Also we had downlights that leak air which I've been replacing. I still leave a bit of opening above them so they don't wear out too quickly from heat. You have to check local regs and specifications for insulation around downlights due to fire risk, but many modern LED downlights are firesafe when fully covered.

Big heat flow happens through windows, including double glazed windows. Curtains can make a big difference. I've also had good experience with tight-fitted accordion blinds with reflective outer side on sun-facing windows.

Good luck with getting it all sorted.

 

[PoolGate]

Blown in insulation is best for attics. Get yourself a phone flir camera. Well worth it.

Also a ceiling fan would help a lot.

FLIR ONE Gen 3 - Android (USB-C) - Thermal Camera for Smart Phones - with MSX Image Enhancement Technology https://a.co/d/7C4IDE8

 

[Mdragger88]

In our old house we had zero shade & our open living room/kitchen was vaulted ceiling. It was about 1/2 the size of our 900 sq ft house. The rest of the house had 8ft ceilings.
It got so hot in that room we eventually started putting a window unit in during the summer. We had blackout curtains drawn all the time. Ran ceiling fans etc. In the winter I had space heaters in there. Our appropriately sized hvac unit just couldn’t cut it.
When we went to sell/list they sent an inspector out so we wouldn’t have any surprises and said we were missing insulation on the wall of the attic that butted up to those rooms. They came & added it for a couple hundred bucks & it was a night & day difference! I felt like a dummy living in misery all those years, not to mention the utility bills!

 

[jmc13]

Blown in insulation is best for attics. Get yourself a phone flir camera. Well worth it.

Also a ceiling fan would help a lot.

FLIR ONE Gen 3 - Android (USB-C) - Thermal Camera for Smart Phones - with MSX Image Enhancement Technology Amazon.com

We have ceiling fans in every room including the living room and loft, we replaced all ceiling fans and light fixtures with energy star certified. The windows are all energy star certified for our climate. We have 3 inch wood blinds on all windows and use double layered blackout curtains. I have smart thermostats and replace the filters on run time, not day to make sure they aren't getting 700-800 hours in the summer and 50 in the winter. When they replaced the HVAC systems they did move some of the insulation, but I'm also assuming when they were building it, they skipped corners and the vaulted section is probably bare. A friend mentioned a thermal camera as well. I will look into the camera thank you, because at least I can visually see what I already think.

 

[aarogb]

I posted about this same topic on another forum I am part of. Glad to know I am not the only one!

One thing they mentioned is having your air ducts tested for leaks. My power company offers rebates if leaks are detected then sealed a certain amount. You did mention your unit is only 10 months old when you bought the house, did they replace the air ducts with the unit?

My unit is 17 years old, and the ducts at least that old as well, can't wait to see what the difference is when the unit bites the dust, and we upgrade to a more efficient one.

 

[jmc13]

I posted about this same topic on another forum I am part of. Glad to know I am not the only one!

One thing they mentioned is having your air ducts tested for leaks. My power company offers rebates if leaks are detected then sealed a certain amount. You did mention your unit is only 10 months old when you bought the house, did they replace the air ducts with the unit?

My unit is 17 years old, and the ducts at least that old as well, can't wait to see what the difference is when the unit bites the dust, and we upgrade to a more efficient one.

Our housing inspector was really great checking that stuff out, he said he didn't see any issues, he mentioned not seeing dust accumulation around insulation or having a lot of dust when the systems are on. He did mention the lack of insulation in some areas, and none around the new units. I very rarely have to dust once the windows and doors were replaced. I can feel plenty of air when the system is on. Long story short, there are Solar panels on the house. The solar company recommended a new roof, HVAC units with new ducts, and pool pump. They did everything before the panels were installed except the ducts. I have their old bills, and I can see their summer usage before and after with no thermostat adjustment. By accident they became more energy efficient, but it still didn't stop the fact that the upstairs in general is overreacting to the weather, which is why I had no issue replacing the windows and doors. It also makes it harder to pay for insulation when my main reason would be to reduce my bills and I don't have an electric bill. However, less A/C should be longer maintained equipment. Everyone in the neighborhood complains about their electric bill, so I know with our improvements we use less, and we are set 2 degrees colder, however, I still have the same issue as the neighbors with the upstairs struggling on super hot days, and we all have the same house model and vaulted ceilings, so it always takes me back to insulation or lack there of in the vaulted section as that is the entire master which is almost 500 sq ft.

 

[superdave5599]

I don't have numbers because it was several years ago, but I did add blown in insulation in my attic at my first home years ago, and it made a difference in comfort summer and winter.

Also, when I redid my roof a few years ago, I went from one to three "whirly-bird" attic vents. That made a huge difference in the heat in the attic in the summer time. Just a week or two, our renter (we bought the current house over the winter and are renting the old house) replaced the furnace filter (furnace and AC is in the attic of that house) and he commented on being surprised at how pleasant the temperature was up there. I went with dark shingles and so I probably over-ventilated it a little, but reducing the heat build up in the attic surely helps a lot with not having the house get as hot.