CA solar/PW folks: what HVAC unit would you purchase today?

[Dukeybootie]

Currently have a single stage Carrier 13 SEER unit that is...okay. Has broken down three times in six years so far but no major $$$ repairs needed along the way. With the current heat wave, I can run the Carrier unit off-grid but not for more than 8-10 hours before draining the two Powerwalls.

Looking at eventual replacement in five years or so but wanted to see what all the smart folks here think of the current HVAC field and technology.

Some questions:
-Worth it to upgrade to a variable speed compressor unit to minimize PW2 drain? Not planning on moving from current home for decades.
-Are variable speed compressors reliable enough yet?
-Is Amana a good HVAC company (they seem to have the best warranty)? If purchasing today, the AVXC20 looks like a top choice.

If there are folks here with experience running a variable speed compressor unit with solar/PWs, I would love to hear your thoughts. Thanks!

 

[Ampster]

I don't know the specifics but varable speed compressors are inverter driven and are also soft start. I looked into doing that when we moved into our house and compressor wasn't working. There are some modifications that might have to be done to the control mechanisms but that may have been because I was going to upgrade my fan to variable speed as well..

My new refrigerator is inverter driven and I never hear it running and the savings from the EPA tag were impressive.

 

[holeydonut]

Whatever you do, DO NOT GET A LENNOX. I've had just a complete *sugar* show experience with their contractors. When I got local Lennox Industries representatives involved to help remedy with the installer, they were initially difficult to work with and condescending. I had to write a letter to their Texas HQ to tell them I was materially mislead in the sales pitch and install process. Then they came around to help me get things righted.

Keep in mind, I bought two full residential systems (I spent over $30k) in February of 2020 so this isn't COVID related. But, I can tell you the indoor air quality add-ons are worth it if you get good pricing.

My new air handlers (blowers) take about 50 watts a piece when running constantly (like 16 hours a day) to move air in the home. This constant airflow, coupled with MERV-16 filters and UV air handling have made a huge difference on allergy reduction and comfort in the home. The dual stage AC has also helped me maintain a constant indoor air temperature without breaking the bank.

Anyway, whoever you go with - make sure they'll install "soft starts" (aka "secure starts") in your compressor units to lower the inrush current demand of the hardware. This will help you get the best experience with the Powerwalls.

If I had this whole HVAC-crap-fest to re-do... I'd get Bryant hardware. Bryant had same features as Lennox for about 2/3 the price. I was just a complete moron and got Lennox mistakenly thinking they were better.

 

[nwdiver]

Currently have a single stage Carrier 13 SEER unit that is...okay. Has broken down three times in six years so far but no major $$$ repairs needed along the way. With the current heat wave, I can run the Carrier unit off-grid but not for more than 8-10 hours before draining the two Powerwalls.

Looking at eventual replacement in five years or so but wanted to see what all the smart folks here think of the current HVAC field and technology.

Some questions:
-Worth it to upgrade to a variable speed compressor unit to minimize PW2 drain? Not planning on moving from current home for decades.
-Are variable speed compressors reliable enough yet?
-Is Amana a good HVAC company (they seem to have the best warranty)? If purchasing today, the AVXC20 looks like a top choice.

If there are folks here with experience running a variable speed compressor unit with solar/PWs, I would love to hear your thoughts. Thanks!

IMVHO you cannot beat mini-splits. They're VFD driven so there is no starting current and you can cool/heat a single room to preserve battery power.

 

[bkp_duke]

I would strongly consider heat pumps, the tech has improved dramatically in the past 20 years. To the point where even air exchange heat pump systems are far more efficient than any HVAC out there.

I'm still holding out hope that Tesla is going to bring their engineering expertise into this arena and release a kick-ass heat pump at a good price. Would turn the HVAC industry upside down if they did that.

 

[arnolddeleon]

I recently replaced my dead 15 year old 2 stage 3 ton Carrier Infinity heat pump with the 5 stage version. My installer convinced me to go with the 5 stage instead of the "infinite stage" version. I believe the 5 stage version is actually made by another company (LG?) and the other was developed in house. The 5 stage version goes down as low 25% I believe where as the "infinite" one only goes down to 40%. With COVID-19 we are running air conditioning more often and I've been pretty happy with the performance on most days. Basically, when it is running, it almost runs constantly, shifting up and down as needed. I wanted to increase the size but my contractor said we didn't have the duct work to support it. The problem is on record setting days is doesn't have the capacity to cool the entire house. This used to be not an issue, we have it zoned and we didn't really use the upstairs. With our daughter home from college and living in the upstairs and me working at home we have all the zones active. Fortunately we kinda know about the hot days coming so we just make sure we don't let the house get hot (e.g. setback when no one is home, but that doesn't happen at the moment anyway) because recovery will take too long. I also already was doing some precooling before for energy savings so doing that for capacity reasons is not a big deal.

If I was doing an HVAC system from scratch today I would be looking hard at mini splits as @nwdiver recommends. Just before I saw this thread, I was telling my wife if we wanted to add more capacity I would just add a mini-split for upstairs.

 

[RunDeep]

Doing new construction now and I went with a Variable Refrigerant Flow heat pump system from Mitsubishi: Residential System Builder | Mitsubishi Electric You can zone it very finely, down to individual rooms. We have a 5 ton system. It looks like a conventional system from the outside, i.e. registers in each room, etc.

 

[eevee-fan]

13 SEER? Wow, time to replace now. Doesn't the state and utility have incentives to help you get one that would use half the power? Also, agree, make sure to get one that also is a heat pump.

Regarding Mini-Splits, yeah, if you have a bed/bath on the first floor, or a 1 story house, it'd be good to install one to heat/cool just that one room...

 

[strangely]

I replaced my old 13 SEER with a 3 Ton Lennox 20 SEER variable speed heat pump a couple of months ago, and so far I am very impressed with not only how quiet the thing is, but also how little energy it uses. Air quality and comfort also seems better, and I didn't even do the HEPA filter add on.

I had a few goals with replacement:
1) Not to be ripped off.
2) Be able to run off of my single power-wall in backup mode.
3) Get a heat pump to eliminate winter gas usage.

I met all 3 goals. If you are in SoCal and want a referral for the installer, let me know?!

 

[msm859]

Currently have a single stage Carrier 13 SEER unit that is...okay. Has broken down three times in six years so far but no major $$$ repairs needed along the way. With the current heat wave, I can run the Carrier unit off-grid but not for more than 8-10 hours before draining the two Powerwalls.

Looking at eventual replacement in five years or so but wanted to see what all the smart folks here think of the current HVAC field and technology.

Some questions:
-Worth it to upgrade to a variable speed compressor unit to minimize PW2 drain? Not planning on moving from current home for decades.
-Are variable speed compressors reliable enough yet?
-Is Amana a good HVAC company (they seem to have the best warranty)? If purchasing today, the AVXC20 looks like a top choice.

If there are folks here with experience running a variable speed compressor unit with solar/PWs, I would love to hear your thoughts. Thanks!

I have 2 Trane units 5 ton and 4 ton. Variable speed 19 seer dual compressors. Installed when built house 2005. Have had zero problems - super quiet and work great. Go with the best. However, also critical is make sure you have no duct or can leaks. And for comfort make sure you have enough returns strategically placed. I have a boiler and radiant heat so was able to design AC solely for AC - vents high and returns low and a return in each bedroom.

 

[Alonzo]

was able to design AC solely for AC - vents high and returns low and a return in each bedroom.

I admit to ignorance on this issue. It seems like you would want your returns high, so it would be returning warm air to be cooled. If the return is low, aren't you just returning cool air and leaving the warm air in each room?

 

[holeydonut]

I admit to ignorance on this issue. It seems like you would want your returns high, so it would be returning warm air to be cooled. If the return is low, aren't you just returning cool air and leaving the warm air in each room?

You’re right, when a system is cooling, the optimal setup is to have the returns up high. And in the winter you’d want the returns low.

In a climate region that experiences both hot summer and cold winter, you’d want to have a pair of returns in every room that you could turn on/off.

Unfortunately most homes are constructed quick and cheaply to maximize usable space. Most air handlers are oriented to blow upward to maximize space. So you’ll probably just see high supply in each room and low return in a single spot near the air handler since that’s cheapest.

 

[msm859]

I admit to ignorance on this issue. It seems like you would want your returns high, so it would be returning warm air to be cooled. If the return is low, aren't you just returning cool air and leaving the warm air in each room?

Well actually I think it is more important that the vents and the returns are Opposite. My vents are all high so that there is a cross flow of the air entering the room from high and going down (to the opposite side) to the return that sucks it in. I can tell you that is absolutely works perfect and we do not have any hot rooms. The vents are generally on the exterior walls above windows or doors. The returns are also strategically placed for cross air flow - downstairs has 5 returns. Upstairs has 4 - although upstairs does have 1 return high in the central hall.

 

[wwu123]

A few years ago, while trying to address temperature differences between rooms and stratification between upstairs and downstairs, I came across this series of five blog posts about supply register (vent) location:

The Four Schools of Thought on Ceiling Register Locations

While the hot air rises, cold air sinks adage can matter a bit, the more important thing is promoting circulation and mixing of the supply air with the room air. Then a number of high or low locations for the supply air CAN work - but using the proper 1-, 2-, 3-, or 4-way supply register is important for pushing the air in the right direction to promote circulation. That generally means using the register direction to push the air in the opposite direction(s) than it would naturally flow along the path of least resistance to the room return.

My case was a common example where there is no return grille in the room, so the return path is the underdoor cutout to a hallway return grille. Any my supply vents were all in the ceiling, but the problem rooms were too cold, so how to get the warm furnace air from a high supply register around the room? Solution was to replace the cheap stamped two-direction registers with adjustable bar type 1-direction ones, and orient the along the ceiling away from the door. So even though it's pushing the warm furnace air along the ceiling first, rather than directly down, it sets up a modest but steady circulation that will uitlimately bring the warmer air down along the opposite wall.

 

[holeydonut]

A few years ago, while trying to address temperature differences between rooms and stratification between upstairs and downstairs, I came across this series of five blog posts about supply register (vent) location:

The Four Schools of Thought on Ceiling Register Locations

While the hot air rises, cold air sinks adage can matter a bit, the more important thing is promoting circulation and mixing of the supply air with the room air. Then a number of high or low locations for the supply air CAN work - but using the proper 1-, 2-, 3-, or 4-way supply register is important for pushing the air in the right direction to promote circulation. That generally means using the register direction to push the air in the opposite direction(s) than it would naturally flow along the path of least resistance to the room return.

My case was a common example where there is no return grille in the room, so the return path is the underdoor cutout to a hallway return grille. Any my supply vents were all in the ceiling, but the problem rooms were too cold, so how to get the warm furnace air from a high supply register around the room? Solution was to replace the cheap stamped two-direction registers with adjustable bar type 1-direction ones, and orient the along the ceiling away from the door. So even though it's pushing the warm furnace air along the ceiling first, rather than directly down, it sets up a modest but steady circulation that will uitlimately bring the warmer air down along the opposite wall.

Undercutting a doorway with a 1" gap between the door and the floor doesn't really allow enough air to come out of the bedroom and into the hall. You can consider a Return Air Pathway on the door itself to increase the flow and get you better results.

Perfect Balance In-Door Air Pressure Relief System

Although what MSM859 has is the most ideal; I wonder who his architect is haha.

 

[msm859]

Undercutting a doorway with a 1" gap between the door and the floor doesn't really allow enough air to come out of the bedroom and into the hall. You can consider a Return Air Pathway on the door itself to increase the flow and get you better results.

Perfect Balance In-Door Air Pressure Relief System

Although what MSM859 has is the most ideal; I wonder who his architect is haha.

Well thank you. I did have the advantage of only having to think about AC with my separate radiant heat system. The reality is the extra costs to build it right is nominal compared to the increased comfort - too bad it isn't done more often. Oh, and thanks again - I was the architect - designed the house with a lot of different things. Steel framing, radiant heat, spray foam insulation.......I installed all the vents and returns and had the HVAC guys do all the ducting.