Will a ductless split system work in an apartment complex?

Question

Hi folks. I am looking at an apartment complex that has a forty year old boiler/chiller system that will cost up to $125K to replace. One option is to replace it with a split ductless systems, which may cost as much, but will be as little as half the energy cost when complete. Does anyone have experience with this to recommend options, and what to stay away from?

V/R

Roy N. · Answer

Amy:

The ductless heat-pumps have been performing well.  We have found the Fujitsu Halcyon a slightly better solution for our environment than the Mitsubishi Mr. Slim: it has a little stronger heating performance than the Mitsubishi, though the user interface on the Mr. Slim is preferable.

In an environment such as yours were cooling will be in equal or greater demand than heating, I would opt for the Mitsubishi.

The deal for the larger (80-unit) building referenced above did not happen, so we did not have the opportunity to retrofit that building.

Amy Hu · Answer

Thanks for the information. It's been 3 years. How have the mini splits performed in your smaller buildings? Have you decided to install it on your larger building?

Presley Reeves · Answer

Thanks Roy, and Bill. I too like the idea of shifting the utility bill to the tenant.  I just don't see continuing with a forty year old system.  As you pointed out, the main thing to watch for is maintaining, or improving the comfort of the residents.  I appreciate everyone's thoughts on this.

Roy N. · Answer

@Presley Reeves

My message will differ a little from Steve Troth.  While there are high efficiency natural gas (94-96 AFUE) and oil (85 - 88% AFUE) boilers available, they will not match the efficiency of a modern ducted or ductless heat pump.  If there is a sufficient discrepancy between the cost of fuels (gas or oil versus electricity), a boiler may be more cost effective during the heating season (but unlikely).

Two other advantages of ductless heat pumps that a central boiler cannot deliver are:

a) air conditioning (chillers and hydronic baseboards are simply not the same).

b) placement of the heating/cooling costs in the hands of the tenants.

That said you need to look at the layout of the individual units to determine if they are conducive to being heated with a single ductless heat pump.  They may still be a need for auxiliary heat (electric baseboards) in bedrooms - or all areas - either from a regulatory or practical position.

Another thing to consider are improvements to the building envelope - air sealing, insulation, windows, doors, etc - will have a bigger impact on building performance than changing out the type of HVAC.

We have removed a central HVAC in two smaller buildings (4 & 6 units) and replaced it with ductless split and auxiliary electric baseboard and are pleased with the results.   The external units were mounted 6-8' off the ground - more so to keep small fingers away from harm then out of a concern for theft.

We are presently dancing on a larger building which was constructed during the 1980s at the height of electric baseboard madness.  Our plans for this building would see a ductless heat pump installed in each unit as they are renovated.

Bill Gulley · Answer

Well, I'm not an HVAC expert, but I do like the mini's, I would think the electrical system could be sufficiently fused and backed up to protect the electronics, I've not had an issue but haven't really used mine too much either ( a cabin retreat). I expect 20 years out of the Mitsubishi. Any future replace of a zone won't break the bank.

Condensers on a roof mount takes care of them walking off.

My preference is always separate meters and tenants paying utilities, that can be achieved with the mini split.

I doubt you will be getting anything at all that was built like a tank and that will last 40 years again, seems a boiler is a boiler, so long as it's safe, never owned one that was in service.

My preference, not with much expertise, they are quiet, economical, easily replaced, remote control and at the unit, condensers can be mounted anywhere that can drain. Electric is pretty cheap here. I also prefer the fireplace too, LOL. :)

Presley Reeves · Answer

Hi Steve,

Thanks! This does indeed help.  I have not bought the property yet, and need to see if I can negotiate this with the seller.  I don't believe I should pay for deferred maintenance when the property owner had the opportunity to depreciate this, so this is a point for us to come to terms with.  Many thanks, much appreciated!

Steve T. · Answer

I am a class A hvac mechanic and contractor, and there is no right or wrong way to heat/cool a bldg.

You got 40 yrs out of your old system, and a new one should last another 40.

Ductless splits will last 10-15 years, if someone does not steal the outside units. Plus, ever seen what a power surge or a brownout can do to a mini split? It isn't pretty.  They get that high efficiency from a Lot of sensitive, expensive components.  Its like comparing a semi truck to a Honda, both are built really well, but one is a lot heavier duty than the other.

I would recommend bite the bullet, and get the boiler/chiller combo. There are some really high efficiency units out there now, that can almost compete with mini splits.

Plus, you have control over when heat/cool season starts /ends with the b/c system.

Hope this helped.