Question:
I'm considering CENTRAL AIR Conditioning for my home.
What system(s) are recommended?
How long will it take?
Will there be much cutting? (ceilings, floors)
What are the range of costs?
Answer:
Whereas the ideal heating system should be as close to the floor as
possible, the ideal cooling system should be as close to the ceiling as
possible.
Three options are available.
1. Running ducts in the attic.
If attic space and access is good, you could run all your ducts in the
attic. You will need to route your insulation above that, but that is a
minor expense compared to the rest. You will have to cut access holes in
the ceilings (for the grilles), preferably close to the exterior walls,
so that you get good air distribution.
You could then place the cooling unit in the garage or outdoors (not to
close to neighbours or they might complain, and you might have noise
level bylaws to respect), and the fan either on the cooling unit itself
or in the basement. To go from the basement to the ceiling, a wardrobe
could be an easy way up. Expect to loose some storage space however.
By the way, I don't like the idea of a fan in the attic as it will be a
little noisier than in the basement. You can however get an almost
silent unit for that.
2. Running ducts in the basement.
A fairly decent option if your basement is not finished or if you have a
crawl space with good access.
On the plus side, running ducts will probably be easier and you could
also use the same ducts during the heating season if you eventually
decide to replace your hot water heating system.
On the down side, throwing cool air on the floor will mean greater air
stratification: very cool floors, yet warm ceilings. You could limit
that problem by having ceiling fans in all rooms working at low
velocity.
3. Using a decentralised system (Sony and Hitachi have some to offer).
Basically, the A/C condenser is outdoors, and you only have water pipes
going to the different rooms. In each of the rooms you want to cool, you
need to install close to the ceiling a unit that looks like an oversize
window air conditioner. Each of the rooms is indivially controlled.
However, this works best if only two or three units cool the whole house
(open environments, for example).
On the downside, there is a fan in the unit. I have not measured noise
levels, but it feels like having the fridge in the room you are. Some
hotels use that kind of system for cooling and heating, and it is not my
idea of a pleasant night of sleep.
Because we have a well-insulated first story house, we would need an air
conditioner two weeks per year, so I have not looked into specific brand
names and I don't have first hand experience with any of these items.
Around here, one should expect to pay the same to install a hot air
furnace and an air conditioning system: $1500 to $3000 for ductwork
(depending on configuration) and $2000 to $3000 for the unit (depending
on house size). You also need to check how many Amperes they need and if
your existing electrical panel can support that.
I am aware there are gas air conditioners, but I don't know how much
they cost to buy or operate vs electric ones.
As for buying window air conditioners, I would recommend that as a short
term solution only if you can live with two or three units. If you buy 8
units, it will probably cost you almost as much as a central system, and
it will cost you 2 or 3 times more to operate them.
