Whole House/Garage Minisplit Install!

[jserr68594]

I am looking for opinions on my proposed mini split installation for my house. I do not have ductwork and have no interest in installing a traditional ducted system! I am remodeling down to the studs and plan to run the line sets inside the interior walls and drain the condensate down to the basement drains. What are your thoughts of my plan? Thanks advance!

 

[pcmeiners]

You should show your location in your profile. A main issue is you are over sizing just about all your units, especially with your insulation values. What minisplit manufacturer do you plan to use. You should use the search to see how others have figured their unit sizing, such as below. As per the outside units, the manufactures want you to believe they are really quiet, they are not, I would locate them away from bedrooms, especially not near bedroom windows; also consider the directions of the prevailing wind in considering the unit's placement and mounting direction . Mount units on legs, 10" or more off a slab due to snow and wind blown debris.

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[inphx]

Good to plan now for the condensate drains, can they all be gravity fed to the drain with needed slope?

Also the copper freon lines - any solid support beams between the Condenser and the Unit to consider routing/placement? These have a foam insulator so the penetration hole size needed may be concern for structural beams and if you make them tight - and are self pulling the lines you are passing them trough a few inches at a time...

Also you need (in my case) 4 wire cable strung to each unit - better get that laid in.

On my outside ac disconnects, if i did again, i would put a subpanel for the condenser loads just because now i'm playing games with off grid solar and being able to re-assign loads would be handy.

I did all mini splits in my new home and love it.

 

[Jinks]

They will need replacing some day. I just replaced a 10 year old mini split in my shop. The same manufacturer was one of the more expensive, so I opted for a less expensive unit with heat included (I don't need heat in Fla., but... ) The new unit came complete with a line set. I planned to reuse the existing lines, but the ends didn't match. I could have soldered new ends, but it was easier to just use the included line set. Keep replacement in mind since you won't be able to access your line sets without serious remodeling. I also think you are over sizing the air handlers a little. It's better to be slightly under sized than over size. Cooling too quick doesn't remove enough moisture & you wind up with damp cold air.

 

[jserr68594]

You should show your location in your profile. A main issue is you are over sizing just about all your units, especially with your insulation values. What minisplit manufacturer do you plan to use. You should use the search to see how others have figured their unit sizing, such as below. As per the outside units, the manufactures want you to believe they are really quiet, they are not, I would locate them away from bedrooms, especially not near bedroom windows; also consider the directions of the prevailing wind in considering the unit's placement and mounting direction . Mount units on legs, 10" or more off a slab due to snow and wind blown debris.

Search results for query: minisplit install

www.garagejournal.com

Search results for query: minisplit sizing

www.garagejournal.com

I am in Northwest Ohio. I know that the systems are oversized, but with the inverters, the BTU range is quite dramatic. For example, a 9K unit ranges between 3000 and 10000 BTUS. I know for cooling I am oversized, but for heating I am not based on what I have read. That is my biggest concern as the minisplits are my sole heat source. I only have one location where the outdoor unit can go unfortunately. The bedroom they are going to be located outside of is a spare though. Thanks for your response!

 

[jserr68594]

Good to plan now for the condensate drains, can they all be gravity fed to the drain with needed slope?

Also the copper freon lines - any solid support beams between the Condenser and the Unit to consider routing/placement? These have a foam insulator so the penetration hole size needed may be concern for structural beams and if you make them tight - and are self pulling the lines you are passing them trough a few inches at a time...

Also you need (in my case) 4 wire cable strung to each unit - better get that laid in.

On my outside ac disconnects, if i did again, i would put a subpanel for the condenser loads just because now i'm playing games with off grid solar and being able to re-assign loads would be handy.

I did all mini splits in my new home and love it.

Yes, I am going to gravity drain the condensate into the basement plumbing. I am going to run the linesets all under the joists. The area of the house they will be in is a crawl space (All of the upstairs bedrooms have a nice 4 ft crawl under them). Thanks for your response!

 

[jserr68594]

They will need replacing some day. I just replaced a 10 year old mini split in my shop. The same manufacturer was one of the more expensive, so I opted for a less expensive unit with heat included (I don't need heat in Fla., but... ) The new unit came complete with a line set. I planned to reuse the existing lines, but the ends didn't match. I could have soldered new ends, but it was easier to just use the included line set. Keep replacement in mind since you won't be able to access your line sets without serious remodeling. I also think you are over sizing the air handlers a little. It's better to be slightly under sized than over size. Cooling too quick doesn't remove enough moisture & you wind up with damp cold air.

I know that I am for sure oversized for cooling, but with the wide range of BTU coverage (For example, the 9K will run 3000 to 10000 BTUs), I feel that the concern is minimal. I am more worried about having enough BTUs for heating as this will be my only heat source, which is why I have opted to oversize a little.

 

[housewolf]

You should show your location in your profile. A main issue is you are over sizing just about all your units, especially with your insulation values. What minisplit manufacturer do you plan to use. You should use the search to see how others have figured their unit sizing, such as below. As per the outside units, the manufactures want you to believe they are really quiet, they are not, I would locate them away from bedrooms, especially not near bedroom windows; also consider the directions of the prevailing wind in considering the unit's placement and mounting direction . Mount units on legs, 10" or more off a slab due to snow and wind blown debris.

Search results for query: minisplit install

www.garagejournal.com

Search results for query: minisplit sizing

www.garagejournal.com

Im sure you know, but they are not all created equally in regards to sound. I have a Mits unit running two AHUs in a guesthouse that is whisper quiet, it’s hard to tell if it’s even running standing next to it. I have a Daiken in my shop that sounds like it’s grinding rocks in heat pump mode. It’s not quiet when cooling either but works fine in both.

 

[CarBikeGuy70]

Sizing is going to be an issue. You need a good load calculation (your location is important) to start the entire project. Please remember all mini splits are not the same, the devil is in the details(performance specifications). I did a similar install and my load calculations were calling for a smaller system than you are calling for- just food for thought. More is not always better with a mini split. With a system also used as a primary heat source bigger will not always equate to more BTU production in cold climates. You need a unit that can produce heat and do so without having to defrost and struggle to perform. I am in western Ct. and my system can produce an amazing amount of heat to below zero- My suggestion is to take a step back and regroup on your project. You are going to be amazed at how warm or cool a correctly designed system will keep your house. I am on my second mini split system at this time. I did the install on my current house and it is simple and easy if walls are open - and doable if not, just more work.

 

[pcmeiners]

"which is why I have opted to oversize a little."

A little ? Way oversized !

Example, (1) 12kFujitsu as linked below can easily do a 1080aft garage with 2 garage doors 2 windows, r13 walls, r20 ceiling AND my entire attached home (1275sft) if need be in an emergency. As to noise levels, the linked units are quiet, but if the units are push due to demand the outside units fans rev up, just like Mitsubishi units do.
I have (5) extra low temp single zone units as in the link, (2) 12k (one as a spare) and (3) 9k units. You are in NW Ohio, you likely get colder then me, so the extra low temps are a good idea.

https://www.goodlifehvac.ca/images/Fujitsu_LZ_Series.pdf

 

[danski0224]

What are your thoughts of my plan?

You need to find some money in the budget to pay a professional to do a load calculation, equipment sizing and equipment selection. Heat pump capacity goes down as outdoor temperatures fall. One really has to dive into the specifications rather than the sales ads
online.

The low temperature capable ones are not the cheapo DIY ones.

I saw as low as 1 degree on one source for winter design temperatures in Ohio, so the heat pump has to meet your heating loads at that temperature. But, what happens if it gets a little colder for a few days? Will the excess cooling capacity be ok per manufacturer specs?

Then, whether or not it will work is highly dependent on how well the house is built with respect to air infiltration.

These inverters are also highly technical as far as repairs go.

The multi head units have to be installed (piped) exactly as the instructions state, or else they do not work as intended or at all.

 

[justinjoyal]

8.5 ton ?

My advice as a HVAC contractor: get a load calculation.

 

[Jim greengo]

Number 2 seems really over sized to me anyway.

 

[dcg9381]

Yes, I am going to gravity drain the condensate into the basement plumbing. I am going to run the linesets all under the joists. The area of the house they will be in is a crawl space (All of the upstairs bedrooms have a nice 4 ft crawl under them). Thanks for your response!

Don't recommend. I see this commonly in homes in Texas and to me it's a giant no-no. What happens is that someone feeds a condensation line into something like a bathroom sink branch drain. That condensation line (eventually, at least in TX) gets plugged up with the typical slime, it plugs in the sink drain and then the condensate overflows out the sink side. The float switch / aux path is never engaged at the HVAC unit, because water has a path out on the floors below. IMHO, plumbing into drain branches on floors below shouldn't be allowed.

Ohio may not have as big of a problem with this as your AC systems can "rest" and the condensation lines dry out. Ours are wet almost year round and eventually slime up if not kept up with. Just think about what happens if the main drain path clogs for some reason.

I want condensation lines that I can force air through (if necessary) - so consider this when you split them. And I would not feed them into anything other than a 3-4" main for reasons above. Here, they are usually fed to outdoors via 3/4" and it's not "if" they will plug, but when they will plug.

 

[pembol]

You definitely can heat your entire house with mini-splits, but not just any mini-splits, they need to maintain capacity and hopefully efficiency as the outside temperature falls. What brands/units are you looking at?

It also looks like you are probably oversized across the board, you can compensate somewhat for this with the modulation from the head, but with multi-head systems you need to look at the turn down ratio of the compressor. It may be with just a single head calling for heat you may not be able to get the output as low as you would like.