Any one have experience with recent upgrades to HVAC

Romer

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I have two HVAC systems in my house and noticed when they both come one I am using 9kWh of energy total for the house. When they are off, I am under 1kWh usage typically around 0.8 during the day and 0.5ish at night

My HVAC systems are 18 years old and likely not very efficient. Last year when being serviced, the tech said one of my systems is on its last legs, but could have been trying to sell.

I read that going to a 16 or 18 SEER HVAC will reduce electricity by up to 40%, not sure about gas for heat in the winter.

From a Net power usage throughout the year that would be a big chunk against an EV. I would expect to replace my wife's car with an EV within the next 2-5 years

Knowing that my HVAC systems are near their useful life, I wanted to be prepared

What I am asking for is any real use experience with improvements in Electricity and gas by swapping out for a more efficient system.
 

gungriffin

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I am following this just to see what people have to say. I am likely going to try for some of the crazy Denver rebates on solar/HVAC at the start of 2023.

I really want to believe that whole house heat pumps work in our climate, but the cold days seem like they could be an issue. Many of these heat pumps have nat gas backups for the cold days though. Have you given any thought to a heat pump Ken?

My friend just installed a new system with a 2 speed blower and he really likes it. It is incredibly quiet when on the low speed and it has the higher speed for when it is necessary.
 

Romer

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Ryan, my daughter mentioned heat pumps and my brief research said it wouldn't do for those really cold spells we get below zero. Let me know if you find something different
 

Hulk

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My parents have been running a heat pump systems in their house in Missouri for 4 decades. They work well, and the winter temps there are similar to our own. They are both in their 80s now and they keep the house warmer than I consider comfortable. I'd keep this on your list of considerations, Ken.
 

IoN6

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Not really "upgrades", but the place we moved into two years ago had a split-system. It has taken a little getting used to, mainly because there is no insulation in the attic. But overall, super happy with it. Added a single head unit to my sons room last summer as well.
 

Corbet

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I honestly have not had the time to really compare my new gas bill verse old but based off the brief glance I’ve given it since the new boiler I’d say 40% less propane is pretty accurate for us. It’s on auto-pay so most months I don’t even open the mailed bill.

We went from an 18 year old boiler that ran the hot water base board heat and a side arm for DHW. To a new boiler with on demand DHW in December. The whole install experience was miserable but the system has worked well.

We don’t have AC at 8100 feet. So my electric didn’t change much with just a boiler upgrade.
 

DaveInDenver

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My parents have been running a heat pump systems in their house in Missouri for 4 decades. They work well, and the winter temps there are similar to our own. They are both in their 80s now and they keep the house warmer than I consider comfortable. I'd keep this on your list of considerations, Ken.
One difference is Missouri has higher humidity, which has a significant effect on efficiency of heat pumps and air conditioners. There's very key thermodynamic reasons why heat pumps caught on back in Missouri and swamp coolers did not. We tend to think of summer being muggy but that water vapor doesn't go away in the winter even though relative humidity is below 60%. That's not to say a heat pump doesn't work here and technology and our calculation and tolerance for energy use is changing over time. But in a world where coal, propane, natural gas or even electricity feeding forced air was cheap(er) a regular furnace will work better here. In Ken's situation generating his own electricity the calculation does change but the physics won't. A heat pump will work harder for each degree of heat in the winter here than back in MO.
 
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Stuckinthe80s

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My dad was an A/C guy for over 30 years and I worked for him when I was in high school, mostly doing replacements and running duct on new builds. I can remember back then the big deal was going to a 10 seer rating and the significant savings associated with that. If I recall, just going from an 8 to a 10 was around a 30% improvement, at least that is what I can remember pops telling people.

The other thing to note is that the seer rating is the guaranteed efficiency right out the box, fresh from the factory. That efficiency degrades over time so with your system being 18 years old, I would wager it is only running about 60% of what the rating is. Being that old, I'm guessing it is a 10 seer? If it is, then you're only running a 6, maybe 8 seer rating by now. I'm actually surprised you've been able to get 18 years out of it. Modern systems are only designed for around 10 years. You know, because planned obsolescence is a good thing for the environment. :rolleyes:

Anyways, although I have yet to personally change out a system in any house I've owned, I can remember how happy every customer was when I would see them on the 30 day follow up after installing a new unit back then. Out of the dozens and dozens of customers that I went with dad to visit, I don't remember a single one saying it wasn't what they were expecting.
 

60wag

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Anyone here running a geothermal heat pump? My old house had one and practically the only left from the house is the ground loop. We are planning to reuse the old loop with the new construction. Pulling heat out of the ground rather than the air seems to work pretty well.
 

Hulk

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One difference is Missouri has higher humidity, which has a significant effect on efficiency of heat pumps and air conditioners. There's very key thermodynamic reasons why heat pumps caught on back in Missouri and swamp coolers did not. We tend to think of summer being muggy but that water vapor doesn't go away in the winter even though relative humidity is below 60%. That's not to say a heat pump doesn't work here and technology and our calculation and tolerance for energy use is changing over time. But in a world where coal, propane, natural gas or even electricity feeding forced air was cheap(er) a regular furnace will work better here. In Ken's situation generating his own electricity the calculation does change but the physics won't. A heat pump will work harder for each degree of heat in the winter here than back in MO.

Super interesting stuff, Dave. Thanks for this information -- I had no idea that humidity affected the efficiency of heat pump systems!
 

Romer

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Good discussion at last nights meeting. Bruce described who his Geo Thermal worked with a pipe/tube down in the ground where it is always 50 degrees working with a heat pump

Dan talked about his Dual Fuel system that has a Heat pump for AC and above 30 deg heat and when drops below 30, the gas furnace kicks in

Although the Geothermal sounds cool, it would likely require a lot of digging in my yard, but I will look into it more

The Dual Fuel system seems interesting
 

OilHammer

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Nice timing on this thread as I am literally running J calcs right now. I bought a glass house last year and have been remodeling it ever since. Unfortunately, the old 10" boiler vent stack runs right through an area I need to reclaim so I find myself looking at new systems sooner than I planned to save vent space. Similar to Corbet, I have hot water base boards. Old boiler is HUGE- 290kBTU and then a separate 40kBTU water heater. It chews dino farts like nothing I've ever seen. I'm looking at moving to a new condensing combi boiler or boiler with side arm tank. Based on the J calc, my load is more like 108kBTU! I should note that I plan to add radiant floors too for a hybrid approach, but I probably can't do that this year. I'll have to keep some of the baseboards just because of the amount of glass in the main room.

Corbet, I'm really interested to hear more about your system since its very similar. Might save me some expensive mistakes.
 

Corbet

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@OilHammer not sure how you add radiant floor zones. Base board should receive 180° water and radiant floor like 110-120°. I don’t know of a way for one boiler to deliver two different temps at the same time.
 

IoN6

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@OilHammer not sure how you add radiant floor zones. Base board should receive 180° water and radiant floor like 110°. I don’t know of a way for one boiler to deliver two different temps at the same time.

Blend valves.

In-floor should be even lower than that from my research, in the 80ish range. Especially if it under wood flooring.
 

gungriffin

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The HVAC in my house I am remodeling is about 18 years old and nat gas for the furnace. It is Amana for the brand and it was probably the cheapest option available if it is like everything else in the house. I don't feel like making it limp along. I also suspect that if things in the world stay consistent, we are likely looking at a per therm natural gas cost that will peak at 2-3x the present price this winter. With that in mind, I am leaning towards a whole house heat pump system to be installed as soon as the weather gets more mild. If anyone has any resources on selecting a heat pump with a nat gas back up, I would appreciate it. I am leaning towards a Trane. I would also like it to be 2 stage or multi stage. Any additional thoughts are welcomed.

One other big item that I am tackling at the same time as I do this is to airseal the home envelope. To accomplish this, I vacuumed out all of the insulation in the attic. I will be reblowing the insulation once I take care of the framing, electrical, plumbing and air sealing. It is my understanding that airsealing the home envelope can potentially make the biggest difference on power usage for heating and cooling.

@Romer did you ever make any headway on this topic?
 

Romer

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Interesting article. I haven't done a lot more as of yet. Thinking in the fall or spring I will get several quotes to get a better feel for options for my house.
 

gungriffin

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Interesting article. I haven't done a lot more as of yet. Thinking in the fall or spring I will get several quotes to get a better feel for options for my house.

My thinking is quite similar. I will get quotes in a slower month. These 100 degree days are keeping the HVAC guys busy.
 

Shark Bait

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A buddy of mine who is an HVAC installer just suggested a heat pump the other day. Our house is 20 years old and we figure it is about time. He said AC units last 15-20 years and furnace about 20-25. So, we're right in the sweet spot. We're running a 3 1/2 ton AC unit, which is 10 SEER. He suggested an 18 or 20 SEER Bosch heat pump, not geothermal. He thinks it would cut our electricity usage by at least 20%, maybe more. If we combine that with the solar we're also looking at, we may cut our electric bill to almost nothing. That is what we are hoping, anyway. If any of you are interested I can pass along his info.
 
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