5 ton AC technology with Sol-Ark 15K

[TIHI]

If you were trying to plan for a grid outage in FL and have a Sol-Ark 15K, 30kwH battery bank and 11.2kWh solar, what would you look for if you needed 5 tons of AC? I currently have 5 tons upstairs and 5 tons downstairs. The upstairs unit will need to be replaced and I wanted to start researching before it must be replaced. I was wondering what you all have found that works well for this type of setup. Options I have heard of but don't necessarily know much about include
1) Single-stage HP with a soft start (SS)
2) 2-stage HP with SS ( I did read a thread about this)
3) 5-stage HP with variable speed air handler (AH)
4) Inverter type with communications
5) Others?
I'm basically trying to find a system that would work with the SA without needing much attention. I didn't mention yet that I have a 1 ton inverter mini split that would operate seamlessly during an outage but I'm hoping for a suggestion for a similar solution but on a larger scale...5 ton, whole house type with AH. I realize I'd still need to monitor the battery bank, but I feel like there are a lot of you that either have similar questions or have knowledge you have discovered on the topic. Hopefully this is a "cool" topic that lots will benefit from. Please contribute to this thread if you have experience, knowledge, advice or just want to jump in with an opinion. Appreciate you all!

 

[DIYrich]

get a system that is already optimized for solar use.

Single stage vs variable depends upon the area to be cooled. If you are cooling a large open space, the single is fine. If you are cooling a lot of small rooms, and have zoning, then variable is good.

In FL, variable is good to get out the humidity.

I would consider geothermal.

 

[Browse]

I would probably get a multi zone mini-split if your upstairs is mostly bedrooms. If you want to use existing ductwork, I'd go with a variable speed inverter unit with low/no inrush.

 

[Quattrohead]

A 5 ton unit for a house is huge so having two 5 ton units is exceptional, inquiring minds would like to know the setup of your house and how well insulated it is. But yes a variable speed heat pump system like ACIQ, Mr Cool or even the domestic brands are starting to release would suit you so much better.

 

[740GLE]

It’s FL, swamp land is cheap, so is constructing large houses.

Pretty sure it’s humid there ?

 

[Vigo]

Lots of good advice given already in a short number of posts. I would just emphasize the ‘basically no inrush’ benefit of variable compressors because even though you have a 15k inverter, if you ever want to run multiple compressor-equipped appliances at once on it you have to consider the chance of multiple compressors trying to start simultaneously just by bad luck. A variable speed compressor will introduce the least susceptibility of that problem to your system.

 

[Bob in Tucson]

As @Quattrohead implied, 10 tons is quite large for a single-family dwelling. Before choosing equipment, I'd encourage you to consider insulating the building envelope as much as is practical. Also, run the Manual J calculations to get an idea of heating and cooling loads for each floor or hire someone to do it; ideally, someone who does not sell equipment.

Personally, having made the move to inverter-driven equipment, I would never go back to conventional equipment. It's more efficient, quieter, more comfortable, etc.

 

[TIHI]

A 5 ton unit for a house is huge so having two 5 ton units is exceptional, inquiring minds would like to know the setup of your house and how well insulated it is. But yes a variable speed heat pump system like ACIQ, Mr Cool or even the domestic brands are starting to release would suit you so much better.

Thanks for the quick input so far. I'll just reply to this one but give some additional info mentioned in the other replies as well. Great info and insight thus far. For the setup of my house, I do have a ducted system and will continue with that infrastructure, at least in this house. My layout consists of a 2-story house where one 5-ton unit cools/heats the 1st floor during the day (living) and the older 5-ton runs upstairs at night where the bedrooms are (still living, but asleep ). I haven't heard of ACIQ before but it looks pretty neat and I do have a Mr. Cool mini, but also see, as you point out, they have whole house ducted as well. I didn't see many reviews for ACIQ yet and will be interested to see how they do in the 5 ton space. I really like the idea of an inverter style unit outside with a duct-connected air handler inside. I thought about DIY'ing it but would really rather have it installed since I'm pretty sure a new line-set will be needed this time and it is not going to be easy. The house insulation is pretty good but the windows could be better. I'm fortunate that the people living here are perfectly comfortable at 78F so I don't even run things very hard. I just need them to ease into their cycles. Hopefully that helps.
@DIYrich mentioned variable for humidity and I would agree. My 1st floor unit is a variable speed Carrier Infinity and it has a "Dehum" mode that is slower than Stage-1 to just remove humidity when temp has already been attained in the summer. I would just go for another one of those units upstairs but they are expensive and seem to need specialized parts and service. Mine is 6.5 years old and the blower motor just went last week (part of the reason I'm on here trying to get ahead of my next purchase) and 5 days later today, we're still waiting for them to get the part. The part, not labor is covered by warranty, but still need to get the part from them.
@Browse is also pointing in the direction I think I want to go, "variable speed inverter unit with low/no inrush" I guess, I'm just curious about which brand/models have a good track record so I can start getting some quotes.
@740GLE your statements were very accurate until the last couple of years. We have seen house prices and building materials skyrocket and I think I heard, 36,000 people a month are moving here and paying prices Floridians aren't used to. It's crazy down here.
Thanks and keep the idea contributions coming. I'm digging into your ideas to see if I can find a good fit that I can hopefully report back on in a year.

 

[TIHI]

As @Quattrohead implied, 10 tons is quite large for a single-family dwelling. Before choosing equipment, I'd encourage you to consider insulating the building envelope as much as is practical. Also, run the Manual J calculations to get an idea of heating and cooling loads for each floor or hire someone to do it; ideally, someone who does not sell equipment.

Personally, having made the move to inverter-driven equipment, I would never go back to conventional equipment. It's more efficient, quieter, more comfortable, etc.

Hi Bob, Thanks!, Just sent a reply as your post came in that talks about some points you mentioned. Before solar, my electric bill was only $140 with 10 tons of AC. Now it is $0 but still have to pay the $21 connection fee for the grid connection. What equipment are you using? Is it ducted? I love mini splits, but really need to stick with the ducted in my situation.

 

[740GLE]

@740GLE your statements were very accurate until the last couple of years. We have seen house prices and building materials skyrocket and I think I heard, 36,000 people a month are moving here and paying prices Floridians aren't used to. It's crazy down here.
Thanks and keep the idea contributions coming. I'm digging into your ideas to see if I can find a good fit that I can hopefully report back on in a year.

Prices are going up in FL, but guess what, prob still way cheaper than the price increases from where all those people are moving from ?

 

[Bob in Tucson]

What equipment are you using? Is it ducted? I love mini splits, but really need to stick with the ducted in my situation.

I went with Mitsubishi equipment. They and a few other brands make ducted air handlers for situations like yours; I think theirs maxes out at 3 tons. I actually bought one but switched to ductless once I saw that my existing ducts were rusted through! ?

 

[SolarRich]

If you need 5 tons, perhaps you should insulate the building.

 

[Vigo]

As a Texan im thinking there’s a limit to how many times you can say ‘your building must not be well insulated’ before you just have to admit that your local experiences just dont match up with conditions elsewhere. Heat index in my city yesterday was 117f. Two story adds a hurdle because unless you separate the upper and lower floors from air exchange then cooling the upper floor becomes very inefficient because cold air literally ‘goes downstairs’ and all the heat the 1st floor is picking up through windows/walls gets added to the heat load of the 2nd floor. Cooling some bedrooms with closed doors overnight with a zoned system is making the best of it, but its still going to take a little more than some downstairs bedrooms would. Thats gonna be life with a big 2 story in Florida. Oh well, its certainly cheaper than moving to wherever all the economic refugees are flowing in from!

 

[740GLE]

If you need 5 tons, perhaps you should insulate the building.

2x 5 tons ?

 

[740GLE]

As a Texan im thinking there’s a limit to how many times you can say ‘your building must not be well insulated’ before you just have to admit that your local experiences just dont match up with conditions elsewhere. Heat index in my city yesterday was 117f. Two story adds a hurdle because unless you separate the upper and lower floors from air exchange then cooling the upper floor becomes very inefficient because cold air literally ‘goes downstairs’ and all the heat the 1st floor is picking up through windows/walls gets added to the heat load of the 2nd floor. Cooling some bedrooms with closed doors overnight with a zoned system is making the best of it, but it’s still going to take a little more than some downstairs bedrooms would. Thats gonna be life with a big 2 story in Florida. Oh well, it’s certainly cheaper than moving to wherever all the economic refugees are flowing in from!

Agreed we run our single upstairs 12k mini split unit and it cools enough to trickle down so that the downstairs unit isn’t needed until temps are above 90f.

 

[Danke]

In FL, variable is good to get out the humidity.

I would consider geothermal.

For a DIYer. Any brands to recommend that sell directly to end customer besides Mr. Cool? Heat Pump furnace for cooling and heating.

 

[TIHI]

If you need 5 tons, perhaps you should insulate the building.

Since I already have great insulation, I think other factors, that are considered when doing a proper load calculation, come into play. Location, size, shade, windows, etc... I found this site that lets you do a rough estimate by taking those items into account. I would love to do less than 5 tons for upstairs, but you don't want to be undersized on the hottest day of the year. Looks like I need more than 10 tons but I'd rather just find my next 5 ton unit that will play well with my solar setup (some type of inverter solution I'm hoping if I can find a ducted solution), runs quiet and keeps the house comfortable .

 

[Nobodybusiness]

As a Texan im thinking there’s a limit to how many times you can say ‘your building must not be well insulated’ before you just have to admit that your local experiences just dont match up with conditions elsewhere. Heat index in my city yesterday was 117f. Two story adds a hurdle because unless you separate the upper and lower floors from air exchange then cooling the upper floor becomes very inefficient because cold air literally ‘goes downstairs’ and all the heat the 1st floor is picking up through windows/walls gets added to the heat load of the 2nd floor. Cooling some bedrooms with closed doors overnight with a zoned system is making the best of it, but its still going to take a little more than some downstairs bedrooms would. Thats gonna be life with a big 2 story in Florida. Oh well, its certainly cheaper than moving to wherever all the economic refugees are flowing in from!

Once that second floor becomes heat soaked it takes a lot of cooling to take the heat down.

 

[ruralsolar]

For a DIYer. Any brands to recommend that sell directly to end customer besides Mr. Cool? Heat Pump furnace for cooling and heating.

Heat Pump Furnace meaning a replacement of your current AC and gas furnace, not sure of any that are listed as "DIY". Watching YouTube University though shows that "most" units really you need a vacuum pump and appropriate gauges. One option is find a friendly HVAC person that will let you buy the equipment wherever you can and then have them install it at a reasonable price.

I'm biased actually against refrigerant based system after installing all hydronic in my new home. I do realize though that new construction makes this much easier over a retrofit and it is not for everyone. That said though, the DIY friendliness of hydronics coupled with a monobloc air to water heat pump is really hard to beat.

 

[Danke]

Heat Pump Furnace meaning a replacement of your current AC and gas furnace, not sure of any that are listed as "DIY". Watching YouTube University though shows that "most" units really you need a vacuum pump and appropriate gauges. One option is find a friendly HVAC person that will let you buy the equipment wherever you can and then have them install it at a reasonable price.

I'm biased actually against refrigerant based system after installing all hydronic in my new home. I do realize though that new construction makes this much easier over a retrofit and it is not for everyone. That said though, the DIY friendliness of hydronics coupled with a monobloc air to water heat pump is really hard to beat.

It is a new ducted house, plan on water to air geothermal. Would like a DIY to save some coinage.