Mini Splits versus oil boiler considering maintenance costs

allenm

I've read lots of posts comparing the cost of running the newer high efficiency mini-splits versus an oil boiler. In fact, I've used a couple different calculators using my local New Hampshire factors. No doubt about it, I should save around $1,000 per year in heating energy costs. But what I don't find much said about is comparisons with maintenance costs included.

My Mitsubishi contractor quoted $ per year for a maintenance contract that only covers inspection & cleaning. It would not include any repair costs. Under those circumstances, I didn't even consider it. My plan is to call for a cleaning probably every 3 years. I have 2 systems and expect that to cost about $1,800 every 3 years. So, now with that cost included, I may only be saving $400 per year.

That would mean a return on my investment in 35 years. I think we all know my mini splits will be lucky to last 1/2 that long, so there goes my return on investment.

BTW, I normally spend $250 every 2 years to have my oil boiler serviced and cleaned.

In any case, I would have still bought the mini splits, except I would have got lower priced models mainly for air conditioning.

Robert O'Brien

Going to need more frequent cleaning when used for both heating & cooling. My cooling only needs it annually.

Jamie Hall

I see nothing wrong with your arithmetic...

Hot_water_fan

Pricing is not allowed, right?

Anyway, yes, ductless "minisplits" are definitely labor intensive to clean. But you're comparing a boiler which cannot provide AC to a heat pump which can, so you're comparing apples to oranges. How much is boiler + AC maintenance vs. heat pump maintenance?

Teemok

Oil will not cool your home if that might be used at times. The inverters that drive the compressor and the control boards have some sensitive electronics compared to oil burners. Grid stability electricity quality problems is a factor. Snow levels and very very cold present problems for HP's. The biggest problem I see with mini splits is refrigerant leaks at the line set flare connection. Payback gone. Cleaning and inspections are simple to do. The 15 year stability of the two energy sources is something to ponder. If not burning oil is seen as a benefit there's that too. How your electricity is made is another consideration if you're inclined.

pecmsg

Along with maintenance cost is life cycle cost. 

Minis 7 1/2- 10 years average life. 

Central heat pump 10 - 15 years
Cast iron boiler 20 - 30 years

Steamhead

Keep the boiler. Install mini-splits if you wish, in which case you'd use them in milder weather. The boiler would then serve for the coldest weather and as a backup.

SuperTech

If you only clean your mini splits every 3 years you will end up with disgusting mold buckets on the wall by the time they get cleaned.  

MikeAmann

Having learned all of this above, how attractive are mini-splits to you now?

And thank you for asking this question.

pecmsg

SuperTech said:

If you only clean your mini splits every 3 years you will end up with disgusting mold buckets on the wall by the time they get cleaned.  

Properly sized and installed units do not build up that mold!

EBEBRATT-Ed

@allenm

Dollars are one thing. Comfort is another. Depending on your homes construction and insulation mini splits will likely not provide as much comfort as a boiler in cold weather.

I would do what @Steamhead suggested.

Teemok

All mini split installs are not the same. Brands aside. Multi zone vs single, indoor unit placement and type can make a big difference. The heated space volume, shape, glass, individual zone loads and total loads all should be considered. Comfort level wise a good hydronic system will feel better. Mini splits stir the room to sense air temperature periodically. Some people find that air movement annoying, some don't care or notice it. Neighbors listening to the outdoor unit fan run all night has been an issue. The happiest heat pump owners didn't have a previous high quality heating system and they celebrate burning electricity they made or they know comes from sources they like. Anecdotal and maybe not typical but I installed a mini split for my father in law in 1997-98 it still works. Holds it's original refrigerant, filter and coil spray offs every now and then. Used daily till 4 years ago. Panasonic or Samsung can't remember.

Hot_water_fan

A good thing to keep in mind is that heat pumps and AC are extremely popular and common in the US - much more common than boilers. I think if you asked someone living in places where heat pumps are the predominant HVAC type, they might be more knowledgeable than someone who otherwise has only installed a different form of heat until very recently.