Author Topic: Buying a new house - advice on insulation, HVAC, solar panels, etc  (Read 573 times)

Abe

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Hey everyone, we're moving to Houston and are going to buy a house (couple of them I'm looking at). My plan is to have a contractor look over the AC and insulation status, and determine if anything needs to be changed out. The last time I did this was 10 years ago, so anyone have advice on what's new in terms of AC technology, insulation retrofit, etc?

Also, I want to install solar panels and probably a battery backup (near the Gulf coast so am sure to lose power from a hurricane at some point). Hopefully with an HVAC overhaul, insulation and our heat tolerance the power demand won't be too high. My best estimate from similar houses is a 10kW system would be sufficient for 80-100% power generation. Any advice on good contractors in Texas (willing to pay for their travel from elsewhere if they are really good)? Thanks!

Papa bear

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #1 on: July 26, 2020, 04:51:09 PM »
Check out matt risinger’s YouTube channel and website, the build show. He’s big on air quality, efficiency, insulation, etc., and he’s based in Texas.  You’ll learn a lot!


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Abe

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #2 on: July 26, 2020, 11:10:04 PM »
Thanks for the advice! His videos are helpful!

former player

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #3 on: July 27, 2020, 05:21:58 AM »
Try to buy on high ground?

Dicey

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #4 on: August 01, 2020, 10:40:29 AM »
Can't wait to see where your journey takes you next.

StashingAway

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #5 on: August 01, 2020, 01:43:06 PM »
The big thing is to address building envelope things first. Don't get insulation until you air seal, and don't get a new AC until you fix the previous items. Often if you fix the building envelope you find that you actually need a smaller AC and furnace when you end up replacing them. There's no point in getting solar panels for thousands when you can make your house 20% more efficient for hundreds.

Also, what you want to find is some who can do an Energy Audit (not just a general contractor). A good one will go through your house with a thermal camera and look for air leaks. They will do a blower door test. They will measure the HVAC vents. Some even place sensors that measure humidity and temperature over a week or two. Then they will give you a full report on which will prioritize the order in which you address your house efficiencies.

The "free" energy audits from your local power or window company aren't the same thing. You want a proper expert with thousands of dollars worth of equipment and experience to help you.

We did this and we got a binder report full of pictures and even the option to "re-test" after we work through the major parts. It cost us $500 for a 1600sq ft, house. Bigger houses and locations may cost more.

Often, it's a good idea to live in the house for a year before an audit so you can focus on problems that you notice in different living conditions (but it's not necessary)

Abe

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #6 on: August 01, 2020, 07:51:50 PM »
Thanks for the recommendations. I agree insulation and air-tight envelopes are key. I’m looking at houses this weekend, and the builder for two of them is very into energy efficiency. I’m excited to see what they’ve done, and am meeting then tomorrow to go over the details. The initial looks suggest they’re well sealed, and the windows are all low-E. Couldn’t get a good look at the attics but will be seeing them tomorrow. The others (not new construction) agreed to provide the electricity bill histories and details from their energy audits. Will keep you all posted!

StashingAway

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #7 on: August 02, 2020, 08:55:04 AM »
The others (not new construction) agreed to provide the electricity bill histories and details from their energy audits. Will keep you all posted!

I'd be surprised if they have a proper audit; it's not a common thing for an average homeowner to do. Many have an "audit" done by the utility company where they come and look at the AC, furnace, and insulation and plug some numbers into a basic forumla, but that gives you very little idea of the performance of the building envelope itself. But I am following with interest!

The building envelope is unseen and boring so most people don't really pay attention. But it is far more important to longevity and health than fancy windows or smart thermostats. Even insulation makes some sense to the general population, but if you aren't keeping your healthy air controlled, it doesn't matter how much you insulate it. Air sealing and humidity control are key! If the attic is insulated, you generally won't know how well it is sealed, so the best time to poke your head in is as it's being built. Or do an energy audit.

Same for solar panels and efficient appliances. They're just the icing on the cake of a well designed "green" building. I would much rather spend 10K getting the envelope tight and healthy than the newest fancy gadget.


If you are really interested look into the Passive House system or go on the http://www.greenbuildingtalk.com/ forum
« Last Edit: August 02, 2020, 09:04:07 AM by StashingAway »

theoverlook

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #8 on: August 03, 2020, 09:28:43 AM »

I'd be surprised if they have a proper audit; it's not a common thing for an average homeowner to do. Many have an "audit" done by the utility company where they come and look at the AC, furnace, and insulation and plug some numbers into a basic forumla, but that gives you very little idea of the performance of the building envelope itself.
We had one of the utility company energy audits done, and the auditor did a blower door test and did thermal imaging throughout the house. It was pretty thorough.

StashingAway

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #9 on: August 03, 2020, 10:25:19 AM »

I'd be surprised if they have a proper audit; it's not a common thing for an average homeowner to do. Many have an "audit" done by the utility company where they come and look at the AC, furnace, and insulation and plug some numbers into a basic forumla, but that gives you very little idea of the performance of the building envelope itself.
We had one of the utility company energy audits done, and the auditor did a blower door test and did thermal imaging throughout the house. It was pretty thorough.

Cool! From my experience that is the exception in most areas of the country. But it's great that it is becoming more available!

Abe

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #10 on: August 03, 2020, 10:31:40 PM »
Updates from the field:

We’re in contract for a house now. The owners have recently renovated and replaced the ACs with high efficiency (SEER 16) units. Also the roof is rated at R-40, walls R-16. There are large trees on the front and north sides of the house, which helps with cooling. They’ve been keeping the house at 73 using about 3000kWh per month in the summer and 1000kwh in the winter. We like it at 78 when at home, 84 otherwise, so hopefully can do better. I’d like to get an energy audit and see what can be tightened up before move in day! Deferring solar panels for now, but will see about them in the winter.

Kroaler

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Re: Buying a new house - advice on insulation, HVAC, solar panels, etc
« Reply #11 on: August 04, 2020, 10:59:38 AM »
Excellent!   Something I think is going to catch on in regards to energy efficiency is self monitoring hvac systems.

Systems that keep up with individual motor power draw, and also the cooling efficiency and set an alarm like a check engine light when efficiency isn't optimal.

I think sensi predict by emerson is the closest on the market right now.  It will have the added benefit of taking maintenance on HVAC from reactive to preventative.     - how nice would it be to know one of your motors is using more current due to a failing bearing or something ahead of time and replace it at a convenient time ....