A lot of it depends on your other loads (whether you have an electric hot water heater, range, etc.), but 100 amp service would probably be okay for the heat pump itself, but the auxiliary electric heat could tax your electric service past its limits. It might work if you cut the auxiliary heat down to 5 kw (lower than normal on an installation of this size), which would take your system's total maximum amperage to probably around 35. Given the other loads in a typical house, that's still asking a lot of 100 amps, but theoretically it's possible if your other loads are not excessive.

Installation cost for a standard split system will be high if you do not have any ductwork right now, as you may not if you have a boiler. Instead of a standard split-system heat pump, you may want to look at a packaged unit that does not have ductwork (similar to those in motels and apartments), or a mini-split system, such as Mitsubishi or Sanyo. These would also possibly be more workable given the limited electrical capacity you have.

But, yes, a heat pump can definitely be a worthy replacement for a boiler, especially in an area with moderate winters. You just have to look at how much it's going to cost versus potential savings, which could put you several years from actually saving any money.

Thank you for the speedy reply KY. I do not have duct work, but rather hot water rads. Where can I get some info on the packaged units that you mentioned? Cooling isn`t required, just heat.

At present time we only use the boiler to give a boost to the house perhaps once during the day and it may come on during the night when the temp inside drops below 15C which is the overnite setting on the programmable thermostat. This might even be a foolish idea on my part as we only burn approx 100 gallons of oil per year.

The boiler is aging however (36 years old). To just swap it out for a new olson model I have been quoted 4k total cost. Hence the thought of an air-ro-air heat pump. As I am 62 years of age, payback is somewhat of an issue. We do spend all of our evenings downstairs in the rec-room in front of the new wood insert. nice cozy heat. We also have aluminum wiring, perhaps another issue?

The aluminum wiring is indeed another issue, but probably not related much to this because any type of additional heat you'd put in would be on its own circuit with its own wiring. Almost all houses I've seen have aluminum wiring for their service entrance wiring, and it's not a problem. Aluminum wiring is really only a problem on standard household circuits that have receptacles or switches that were not designed for aluminum, because the expansion and contraction of the aluminum wire (which is greater than that of copper) can cause connections to loosen and get hot. But if you've got receptacles rated for aluminum, or both aluminum and copper, you should not have this problem.

But back to the heat pump issue, since you have no need for cooling, and you are only using 100 gallons of oil per year, I'm going to say the heat pump probably does not make sense. I think in Canada you use Imperial gallons, but I am used to thinking in U.S. gallons, so let's say you're using 120 of those to adjust for the difference in measure. At current U.S. prices that would be about US$500 in oil. Is that about right?

Assuming your boiler is 70 percent efficient, you're using about the same amount of heat you could buy with about 3,500 kilowatt-hours of electric resistance heat (baseboard, fan-forced wall unit, etc.). I think in most parts of Canada your electric rates are pretty reasonable, but even at U.S. 10 cents per kwh, which might be more than what you pay, that's $350 in electricity to duplicate with electric resistance heat what you're paying $500 for with oil, resulting in a $150 savings.

Baseboard heaters cost less than $50 apiece, and you have individual room control, which works well in your situation since you have alternative heat sources available and would just use the electric heat to supplement that. Possibly you could increase your savings further with electric heat by heating only the rooms you need (such as your bedroom(s) at night), whereas the boiler was heating the whole house. You might be able to do it without upgrading your service if you do not install an excessively large amount of wattage, which might be possible given your moderate climate, but you'd want to have an electrician evaluate that.

KY: awesome advice and very perceptive on your part. We used $350 last year for oil and this year it will be just what you guessed (500). assuming it stays at $1.45 per. litre.?

As for elec. baseboard. we have noted with one that we plug in that it works fine on the lower setting (750) watts, but will cut out when run on the 1500 watt setting. This would seem to indicate that any additional baseboards installed can only be 750 watts or less. So am thinking that perhaps a couple of wall-hung elec. heaters might do the trick?

I`m hoping to get close to an overnite burn with the larger and more effecient insert,and while it doesn`t seem to change the temperature much for the upstairs, it nevertheless feels warmer. Thanks again for your much valued advice.

Thanks - I'm glad it was helpful.

If you're already using a portable "plug-in" baseboard heater, this is actually all the more reason why it'd be preferable to get some baseboard heaters (or wall units) permanently installed. The reason your plug-in unit is cutting out on 1500 watts is because its circuit is overloaded. You won't have that problem with the permanently-wired baseboard units, becuase they'll be on circuits big enough to support them, and there won't be any other household loads on those circuits. You could have 5,000 to 6,000 watts of baseboard or wall-unit heaters installed, and with your other heat sources and moderate climate, that might well be enough. You'd probably be looking at an installed cost in the hundreds, or possibly a little over $1,000, but far less than a new boiler or a heat pump. A side benefit is it would make your house safer by taking some load off the rest of your wiring, as you would no longer need plug-in heaters at all.

Thanks again KY: my wife says you are hired auto as a consulant. lol probably couldn`t afford ya. This is a multi-level split (4 levels total). And I can see where you are going with this. heat where you are at the time. the rest is a waste of fuel. Wheras the boiler just heats the whole house, which is a waste.

So, just a matter of the electrician picking out the not oft-used stuff to install the elec. wall heaters? where there is less likely of an overload>?

Do able with 100 amp service? Just 2 of us living here now , so not a whole lot going on at one time. Totally awesome if it can be accomplished?

Yes, in an area such as yours where it's not extremely cold, you can often get by with heating just parts of the house, saving a lot of energy. Even people who live in colder areas can do this during the less-cold parts of the year, such as fall and spring.

What an electrician will do to install the electric wall heaters is run new circuits entirely (new circuit breakers, new wiring). These will not run on your existing wiring, so there should never be any overloads at all -- the circuits will be sized for the amperage of the heating units installed on them.

Whether this is workable on your existing 100 amp service is indeed the big question. Several years ago, I put about 50 amps of electric heat in a house I lived in that had a 100 amp service, and I never had a problem. If you do need to upgrade to 200 amps, that is not always a huge expense.

I would reccomend a geo thermal for your situation. Its a little pricey up front but a seriously effecient system when installed correctly and requires no extra circuits for back up heat strips.

I think geothermal is great, but for someone who needs no cooling and is spending a few hundred bucks a year on heating right now, can you justify an investment in geothermal? I have never heard of a system like that going in for less than $12,000, and some are a lot higher than that.