Any one have experience with recent upgrades to HVAC

[Romer]

I have installed a solar system this past year and that has given me more visibility to energy usage. 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. I see there are even units with a SEER of 22 or 28 for a Lennox signature series that would provide greater savings

Knowing that my HVAC systems are near the end of their useful life, I wanted to be prepared and decide what system I want and even get quotes.

What I am asking for is any real use experience with improvements in Electricity and gas by swapping out for a more efficient system. Curious what SEER and unit you went with and energy usage deltas year over year.

 

[homestead]

Interesting, How big of a solar system did you install?

 

[Romer]

9.9kwh Peak power. 27 panels, two inverters and two LG 16kW battery backups

 

[Blue Poles]

I installed new HVAC equipment on my house about 4-5 years ago. My situation was that my house was cooled by a swamp cooler and heated by a propane furnace (80% efficient burner). Propane is expensive, and swamp coolers are pretty much junk when brand new and don't get better with age.

I went with a Lennox Signature heat pump, 24 SEER, paired with a condensing 96% efficient furnace. I had figured that I needed a 5 ton unit (desert southwest, not much shading, 2100 SF) but the contractor installed a 4 ton unit.

The nice thing about these top end units is that they use variable frequency drives on the fans and compressor so the unit can match the load fairly closely. This is good as it reduces power costs and keeps the house comfortable without large temperature swings or short cycling of the equipment. The heat pump works fine into the 30 degree range, below that it kicked on the propane burner. I ended up using about 75% less propane (the water heater became the biggest propane load). And the electric bill isn't crazy, it's about $175 per month in the summer.

The thermostat is a smart thermostat that is connected to the internet. Lennox emails a monthly report showing you how often and how hard the system runs, and shows heat pump operation vs propane use. My cooling demand never goes above 50%, which means that I probably could have went with a 3 ton unit.

Of course, you pay up front for this. My system was $16K installed, but for me it was worth it. I run the AC whenever I want to and don't think about the electric bill because it won't be a surprise with this system. Sure, I could have bought a cheaper less efficient system for less, but if I did that I would be concerned with the electric bill during the summer. Instead, I paid up front for the top equipment and enjoy it whenever I want.

This year the city extended natural gas lines to my neighborhood, and 6 years ago spending the money to connect to the natural gas would have been an easy decision. With the drastically lower propane use, it became a less desirable option. But I did connect, just so I could kick the propane company to the curb

 

[target2019]

I have installed a solar system this past year and that has given me more visibility to energy usage. 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. I see there are even units with a SEER of 22 or 28 for a Lennox signature series that would provide greater savings

Knowing that my HVAC systems are near the end of their useful life, I wanted to be prepared and decide what system I want and even get quotes.

What I am asking for is any real use experience with improvements in Electricity and gas by swapping out for a more efficient system. Curious what SEER and unit you went with and energy usage deltas year over year.

We replaced two HVAC systems in 2017. The original heating systems were about 40 years old, and the external A/C condensers were somewhat newer, but always a problem.

The line sets were replaced, which was pretty difficult going under slab. We bought matching Rheem systems, maybe 2.5 ton each. It's been awhile, and I have the paperwork. The total cost with 2 years of service was about $15K.

In the first full year of summer the reduction in electric costs was about 1/3 lower. Heating was down maybe 10%. The difference in comfort was well worth the cost. I didn't go for high efficiency either. That was going to require modifications that were questionable (necessary slope, etc.).

The bottom line is that our energy use for both electric and gas always measures as very close to highly efficient neighbors, as they call it. This is for two-story 3,000 sq. ft area in NJ. We stay at 69 in the winter and 77 in the summer.

More efficiency is always better, and there is a question of how much to pay for squeezing more efficiency. State rebates and sales might be significant factors for you.

 

[RobbieB]

Sounds about right for the savings.

My old system was 3 tons and would blow 30 amp fuses.

My new system is 3.5 ton and uses 22 amps. Never blows fuses.

 

[Bamaman]

We live in the MidSouth where winters are moderate and summers are hot. It's 98 degrees today with a Heat Index of 108 degrees.

Our home has a conventional crawl space and room for elaborate ductwork for the 2200 square feet on the downstairs. We have a thru the foundation package heat pump that works very well--especially with 15' to 19' ceilings thru half the downstairs.

Our upstairs has a conventional separate heat pump for 4 bedrooms and 3 baths. I imagine it's a builder's grade 14 SEER unit.

At 10.5 cents per KWH, our electric bill (with water) runs about $275 a month, and $375 a month in Summer. It may hit $400 next bill with these hot temperatures.

If I was going to put in a heat pump today, I'd probably go up one size from 14 SEER. I replaced such a 3 ton unit at our lake house last summer with some air handler sheet metal repairs for $4,200. I had received other prices of $5,300, $7,600 and from $8900-$12K (depending on SEER).

It's just a shame that (1) so many HVAC companies have been bought by manufacturers and (2) there's not more parity in pricing. So many HVAC companies go for the throats of their customers--especially if they aging, retired folks.

 

[RetiredAndLovingIt]

Be sure to check with your Gas and Electric companies to see if you might qualify for their Energy Assistance programs where they replace inefficient gas heaters, ac units water heaters and other appliances for free, weatherize your home and also offer a discount on your monthly bills.

 

[jazz4cash]

Maybe I missed it. Are your systems heat pumps or AC only? That makes a big difference if you modernize.

 

[Romer]

I have two Furnace/AC units. The Furnace's are both Goodman 80% GMS8/GDS8 Gas furnace and it was installed in 2004 when the house was built. The AC units are also Goodman, but not sure what the SEER value is. I need to go look at that

I live in Colorado were it can be below zero for a week a year and multiple weeks in the low 20's

 

[skipro33]

If you are on solar, why care if your AC is efficient or not?
New systems focus on energy conservation, not efficiently. I find they are easily out performed by the older technology. For example, if your current AC Unit can lower intake air by 25 degrees, it will run for a shorter duration than one that can only lower ambient temperature 18 degrees. See the tradeoff? Now which equipment will last longer, the one that can get the job done in less time or more? Called the duty cycle. Even though it used more power up front, it's duty cycle plus wear and tear can make a less efficient unit more cost effective.
Same with washer machine, dishwasher, etc.
And who told you your current system is on its last legs? Machines are repairable for a lot cheaper than replaceable. Add that cost in when determining life time cost of an AC system.

 

[NW-Bound]

9.9kwh Peak power. 27 panels, two inverters and two LG 16kW battery backups

I believe you mean 9.9 kW power, and 2 x 16 kWh battery storage.

A lot of people get the two units of kW and kWh mixed up.

 

[Romer]

I believe you mean 9.9 kW power, and 2 x 16 kWh battery storage.

Actually it is 9.9kwp (peak) and two 16kWh Batteries. Since I am a EE I will attribute that as a typo rather than being confused. Although I am retired now

 

[Romer]

If you are on solar, why care if your AC is efficient or not?
New systems focus on energy conservation, not efficiently. I find they are easily out performed by the older technology. For example, if your current AC Unit can lower intake air by 25 degrees, it will run for a shorter duration than one that can only lower ambient temperature 18 degrees. See the tradeoff? Now which equipment will last longer, the one that can get the job done in less time or more? Called the duty cycle. Even though it used more power up front, it's duty cycle plus wear and tear can make a less efficient unit more cost effective.
Same with washer machine, dishwasher, etc.
And who told you your current system is on its last legs? Machines are repairable for a lot cheaper than replaceable. Add that cost in when determining life time cost of an AC system.

My system is sized well for my current usage. I havent had an electric bill in quite some time.

In the future I can forsee having an EV or maybe two. Since I will likely need to replace my HVAC before then, it would be great if the reduction in a more efficient system helped offset the increase for additional power for an EV


The technician told me one system was near failure requiring about $800 in repairs and recommended replacing soon. One of the heat exchangers is starting to crack and the amp draw on the inducer motor in one unit was at a high level due to age. This was 16 months ago so obviously I did not rush out to get a new one.

They are 18 years old and I am researching so WHEN they fail, I know what I want to do.

I may be proactive get a quote and replace one of the units in the next 2-3 years, if it doesn't fail first. Or I may just wait till they fail.

If and when I replace these, if they help offset an EV in the future, in my view that would help mitigate one of the areas of inflation.

 

[ERD50]

If you are on solar, why care if your AC is efficient or not?
New systems focus on energy conservation, not efficiently. I find they are easily out performed by the older technology. For example, if your current AC Unit can lower intake air by 25 degrees, it will run for a shorter duration than one that can only lower ambient temperature 18 degrees. See the tradeoff? ....

No, I don't think it works like that. You are not doing apples/apples.

First off, I don't think your assumption that a more efficient AC has a lower T-delta is valid. And if it did, to achieve the same rating as the old one, it would need to pump more air through (larger blower and maybe larger ducts inside) to get the same cooling. So it would not be an apples/apples replacement, it would actually be a smaller unit.

And a smaller unit might actually be a good thing (depending). Running longer provides more ability to reduce humidity (if that's a concern, like here in the Midwest).

I ... Now which equipment will last longer, the one that can get the job done in less time or more? Called the duty cycle. Even though it used more power up front, it's duty cycle plus wear and tear can make a less efficient unit more cost effective.
....

Longer running times also means fewer on/off cycles. That can actually improve the lifespan - "short cycling" can create a lot more stress than a constant on. Again, it depends on many things.

-ERD50

 

[NW-Bound]

Actually it is 9.9kwp (peak) and two 16kWh Batteries...

My system is sized well for my current usage. I havent had an electric bill in quite some time...

That's roughly the same size as my DIY system, both in PV production and battery storage.

However, in this Southwest climate where the high routinely hits 115+ (46+C), cooling down at night to 90F (32C) before sunrise, I would need 2x the PV panels and 2x the battery storage to keep the ACs running through the night.

 

[freedomatlast]

I always go for the less electronically complex, lower SEER rated systems. Many times, any reduction in energy cost from the higher SEER rated systems is more than offset by the frequency and cost of repairs of the more complex systems over the life of the system. For example, look up the price of a variable speed fan motor vs. a single or two speed motor and you'll see what I mean.

I was on a consulting job today at a large company and one of the chillers at the facility failed. While waiting as vacuum was being pulled on the system, the HVAC guy from Facilities Services and I were talking about this exact subject and he agreed that the lower SEER rated systems seemed to have a much higher reliability record with less expensive repair costs.

 

[ncbill]

I have installed a solar system this past year and that has given me more visibility to energy usage. 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. I see there are even units with a SEER of 22 or 28 for a Lennox signature series that would provide greater savings

Knowing that my HVAC systems are near the end of their useful life, I wanted to be prepared and decide what system I want and even get quotes.

What I am asking for is any real use experience with improvements in Electricity and gas by swapping out for a more efficient system. Curious what SEER and unit you went with and energy usage deltas year over year.

Yeah, the trick is to find an installer who can properly install such so you actually get that high SEER, assuming a conventional split.

You'll find most HVAC companies won't even bother to do proper calculations...e.g. if you have a 3 ton unit that works for you currently they'll just spec another 3 ton unit in their quote.

 

[Romer]

I was talking with a friend last night who has a Dual Fuel system

It uses a Heat pump for AC and heat down to about 30 deg outside, then it switches over to a furnace for the colder weather. Heat Pumps don't do well below 30 degrees

He did say his heat pump is slower to react then a normal AC and doesn't get quite to the cool level he wants so he augments it with a stand alone AC unit in his Bedroom.

I haven't seen that in other reviews so curious how Heat Pumps do in high heat and any thoughts relative to selection?

 

[homestead]

Our heat pump also runs out steam below freezing. We switch over a pellet stove when that happens. But, for cooling it never has any problems no matter how hot it gets.

 

[ncbill]

I was talking with a friend last night who has a Dual Fuel system

It uses a Heat pump for AC and heat down to about 30 deg outside, then it switches over to a furnace for the colder weather. Heat Pumps don't do well below 30 degrees

He did say his heat pump is slower to react then a normal AC and doesn't get quite to the cool level he wants so he augments it with a stand alone AC unit in his Bedroom.

I haven't seen that in other reviews so curious how Heat Pumps do in high heat and any thoughts relative to selection?

No problems with my heat pump versus the A/C-only unit it replaced.

And I haven't used the heat pump for heat in several years...natural gas is so cheap I just use the 'backup' 80% gas furnace to save wear & tear on the compressor.

 

[Piper20]

In 2018 we had a Carrier model 25VNA 4 ton variable speed Heat Pump installed. Speed varies 50 - 100%, 2-4 ton. At the time the most efficient Carrier made. The newer models vary 25-100%. Came from a 15 YO Trane which had a 2 and 4 ton compressors replaced multiple times under a 10 year extended warranty. The Carrier was 16K with a 10 year warranty. All copper Freon lines replaced and MERV 15 air filter. The manufacturers no longer have their own extended warranty and outsource to another firm.
18.0 SEER, 13.5 EER, and 12.5 HSPF
The Carrier so far has kept the 2400 sq ft house in SE PA at 72 down to zero outside temp without any auxiliary heating. Aux heaters, (3) 5KW heaters are set for -10. Vent temps are 92-100 even down to zero. The Trane it replaced started to struggle below 20. Vent temp was around 82.
AC works great also.
Summer temp set to 74 day 72 night. Winter 72 day 70 night.
The only issue with the scroll compressor is when the set point goes up 1 degree when outside temp is 15 or below they will I call it scream because the will spin up to 7,000 RPM. Once it gets closer to set point that goes away. It’s not that loud but you’ll notice it. They all make the same noise regardless of the manufacturer. Scroll’s are made by 2 companies IIRC.
Energy saving about $10 a month since both units were high efficiency. We use about 14500KW annually. All electric home. The Carrier is much more comfortable both winter and summer.

 

[Rianne]

Longer running times also means fewer on/off cycles. That can actually improve the lifespan - "short cycling" can create a lot more stress than a constant on. Again, it depends on many things.
-ERD50

We bought a high-efficiency Trane HVAC system in 2016. It short-cycles when the temp outside is close to the temp on our thermostat. The HVAC company that installed it has been over 3 times trying to figure it out. Finally, they linked up our phones to the thermostat via an app. I'm always skeptical when someone asks for our wifi password but gave it to him. They have not responded or given us a reason for it doing that.

You just made me wonder if the life span will be shortened because of that short cycling.