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Split System HVAC - One brand or two?

Just so you know, a split system in HVAC industry parlance refers to an exterior condenser and an interior evaporator. These two units work together to provide cooling and, in some cases, heating. Let us suppose that in your split system the inside air handler fails. You need a new one, and find a great deal. But, it's a different brand than the condenser. Can you use it or do the two components have to match?

In Theory Mixing & Matching is Possible

Theoretically speaking, there's no technical reason why you couldn't use a different brand energy efficient heat pump and air handling unit. All heat pumps and air handling units operate with the same basic principles, since there are only so many cost-effective ways to cool air and blow it around a home. The physics isn't the problem. After all, we're not mixing rocket science with brain surgery, but, as they say, the devil is in the details.

Potential Split System Problem Areas

Theory is one thing, but reality is another. If you're going to try to mix heat pump and air handling unit brands, which we don't recommend, then you need to be aware of the following areas where you may experience problems:

Coolant - R-22 and R-410A are the main refrigerants on the market today, but R-22 is due for eventual phase out. A heat pump that uses one and an air handling unit that uses the other cannot work together. While you can always try to flush the coil to remove the older R-22, this isn't easy and risks contamination.
Efficiency - A split system is only as good as the sum of its parts. An energy efficient heat pump rated for 18 SEER performance is not going to pull that off if it's paired with a different brand air handling unit rated for 13 SEER.
Heating - Some air handling units are designed to work with heat pumps, but not all of them are so flexible. If you use an air handling unit brand not built for the heat cycle, this will cause a problem. The kind of problem that ruins systems and wrecks your wallet.
Warranty - Do you like having a warranty on your equipment? Well, if you mix-and-match different brands, you can kiss any warranty goodbye. No manufacturer on the planet is going to honor a warranty when you're using half their stuff and half somebody else's.

Our Recommendation

For a split system, use matching equipment from the same manufacturer. Do not mix and match. Yes, technically, you might be able to get them to work, but it's an absolutely terrible idea for a lot of reasons. Just don't do it!

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Jon

Hi there. I just bought what I thought were both components of a mini split, but much to my surprise, it was only the condenser! So I went to order the air handler and found that there was a two month backorder! So, what to do? And that is why I ended up here, to see if it made sense to find a different manufacturer of the air handler that would work with the condenser. I suppose I could just return the condenser and order the proper product, probably from china, but i thought that I should ask first. Since the unit is new, i suspect that most of the issues you mentioned don't hold here, except for the warranty part. So, What would you do if you were in my shoes, baking away?!

Kevin

I have the opportunity to buy a new, rather cheap Toshiba/carrier outdoor unit, model# RAS-15LAV-UL. The problem I am encountering is finding an air handler/wall unit; I cannot find a matching model number RAS-15LKV-UL. I can find RAS -15EKV-UL, which has the exact same specifications in the user manual as the LKV even down to the dimensions. The outdoor unit for the EKV, the RAS -15EAV-UL has the exact same specs as the LAV I can get, even having the same model compressor. Do you think, given the matching manufacturer and specs, that it would be ok to match a RAS-15LAV-UL outdoor unit with a RAS-15EKV-UL air handler?

Thomas Munnecke

Thanks for the advice.... I had a hybrid heatpump/gas HVAC unit for my home, and the contractor proposed and invoiced me for a system all made by Brand A. But they swapped in a Condenser by a Brand B manufacturer, without my permission or advanced knowledge, so I have a Brand A . Now, the system is throwing strange errors on the thermostat when trying to use the heat pump, and the technicians are at a loss to explain it. They told me that Brand B had a superior guarantee, but in reading the warranty, it gets iffy if it is connected to another manufacturer's equivalent. Is this even legal (I'm in California) to propose and invoice one configuration and then to install another? Is there any way I can confirm that this is not a viable configuration? Thanks for whatever thoughts you might have.

Rob

Hey Ed Obviously if all else is comparable ie. Similar tonnage and similar refrigerant then yes it should work. Seems some of us are just in the market to get people to have to buy new equipment than saving people some hard earned cash...

Anthony

I have a Daikin mini split system the exterior condenser can be used for up to 5 rooms 3 are being used. One room is 150 sq ft the smallest interior air handler they sell is 7000btu, the room gets mold when using the ac very badly. Called Daikin they are no help will not speak to homeowner and my installer is no help. Tried putting in auto, dry and cool settings no better. I was wondering if trying mr. slim 6000 btu unit would help or any other advice would be greatly appreciated. System is less than a year old

Eugene J Desjardins

I have a MrCool 5 ton signature series heatpump bought in 2016 from Ingram’s. One of the problems I have is that I live in northern maine and my heat pump does not work well in cold weather, especially the defrost. Can I install the MrCool universal 5 ton heat pump instead, which seems to be rated for cold climate and think it has a smart defrost instead?

Nick

I just bought ur Mr.cool 5 ton universal and was wondering if hooked it up to a different boxed evap coil like a Goodman for example with matching ratings seer, btu ect would that work ? And if so does that void my warranty?