HVAC Talk-> Mini split systems

[Cafe_to_go]

Hello my DTT friends, I have a question for my Canadian friends in regards to mini split systems, are they commonly used in Canada? I am rehabbing a property in Chicago and so far 2 techs have told me they are no good in Chicago winter climate. Since all the cold front usually comes from Canada who better to ask.

 

[Kamn]

Whats in the house now for heating?

Everyone I know that has a mini split system basically got it for the AC since its ductless and they have a radiant heat system
How well it will heat, I couldn't tell you
Im sure it will all come down to the BTU rating for the heating and how well the house is insulated to be able to retain the heat

 

[Cafe_to_go]

The house had a furnace but was damage to due to water exposure, so currently there is nothing. There will be little to no insulation because I am leaving the brick walls exposed, I know this will hurt but's a rental unit. Will having the proper BTU's and taking into consideration the exposed brick, high ceilings and minimal insulation balance out at the end? I've been doing some research and some tech recommend doing a manual J calculation, it's funny how many tech's don't even use manual J calculations, this according to other tech's.

 

[Kamn]

Do your calculations and see whats out there that may or may not be able to heat that space properly

 

[Grazz256]

Find better HVAC people lol

I know quite a few people who have installed mini-splits in recent years for both heat and cooling. I'm told they cut down on your power bill quite a bit.

I have no idea how cold it gets there but you will probably want a low ambient kit so it will work in cold temps (below like -18C, 0F), and I would still have base boards or something to supplement or use if there is an issue with the mini-split.

Cheers

 

[mydlyfkryzis]

Split sytsems with a heat pump barely heat when it is under 40 degrees F. Out. Below 20 they supply no heat at all. To heat then, they use either electrical resistance heating, or if they are variable speed compressors, they "misfire" the VFD to cause the motor to heat and pump that into the house. Heat Pumps essentially take the heat out of the outside air and move it indoors. When it gets too cold, the refrigerant is ineffective, so it is like there is no heat to move.

Heat pump type units are great in mild climates, like around North Carolina...they are not efficient in New Jersey and north. They will supply heat, but it is electrical resistance heating. You can buy an electric baseboard heater for the same effect.

The mini splits will work in mild weather, and in warm weather for air conditioning (Cooling). But for serious heating needs, unless your electric is $0.05 a KW/hr, They are more costly than gas or oil heat .

I live in Northern NJ. I was considering a "Hybrid system", a unit with a heat pump and a gas furnace. In no scenario was the heat pump less costly then running a 96% gas furnace.

If electric is cheap, an electric baseboard unit would be simpler to operate, with less chance of failure.

My Church put a Dozen Split systems in for the classroom (Against my recommendations - I work for the the largest AC company, BTW). After the first winter they had to add electric baseboard to supplement the heating, as the rooms would drop below 50 degrees. This is when they were occupied.

 

[Grazz256]

I think you are looking at the wrong heat pumps, there are entire series of heat pumps designed for heating in cold climates. check it out
http://www.neep.org/initiatives/high-efficiency-products/emerging-technologies/ashp/cold-climate-air-source-heat-pump

They definitely aren't doing as well as it gets cold out but still producing lots of heat.

Hrm.. did a bit more searching and found this...
http://www.chba.ca/uploads/TRC/May%202013/Cold%20Climate%20Air%20Source%20Heat%20Pumps%20Presentation%20-%20May%202013.pdf

50% energy savings over electric heat, I maybe have to price one of these out for my house..

Cheers

 

[mydlyfkryzis]

Well, good luck with it....As I said, I did an analysis of this for heating my home using the manufacturers analysis program that the Dealers use to size equipment. It would not of saved any money over gas heat, and the first cost was higher than a pure gas system. If you don't have natural gas available, then it may be an acceptable choice....

Read the docs you are looking at carefully, look at supply air temps and how the defrost cycle affects it. If you have any female type people in the house, I know they will be complaining over the temp swings. They heat, but it is not as nice as a good gas heat system.

 

[irk miller]

My Philadelphia rental runs two multi room Mitsubishi splits, one downstairs and one upstairs. I'm getting about $200 more/month on rent for running the splits for a/c. I kept the boiler system in for winter, although the splits probably work well enough. It just made more economical sense at the time not to remove the boiler and radiators. This is a middle row home of 1546 sq ft. The basement is not heated except for the boiler's main feed and return lines running the center of the ceiling, which actually do a good job making the basement comfy.

 

[mydlyfkryzis]

Re: HVAC Talk-> Mini split systems

Philly is slightly south of Canada. Slightly warmer too.
I am familiar with Toshiba units. To get additional heat, they make the motors a little heavier as " misfire" the vfd. Causes the motor to run hot...extra heat then. But never as good as gas. Defrost cycles are the biggest culprit with ashp. Causes cold dips

 

[irk miller]

Re: HVAC Talk-> Mini split systems

Philly is slightly south of Canada. Slightly warmer too.

I'm not trying to compare to Canada, just relaying my actual experience with the units. It's not theoretical experience- I've actually bought them, installed them, lived with them, and I pay for the maintenance on them. It does get below zero in Philly sometimes, and has been known to dump several feet of snow now and then. It's also experience in a middle row, which may or may not be similar to the OP. Exposed brick on an end unit is obviously different then that of a middle unit.