You can't do better ,or cheaper, than with a GSHP. Gas prices are
increasing so this is becoming more so. If you're running an open loop
on that deep well (assumption) you must have very good water to not
have heat exchanger problems. Most recommend closed loop to prevent
contamination. If your water is that good, stay with it. However, a
closed loop would cost less in pumping cost because it uses smaller
pumps and much less electricity. The downside is that it costs alot of
money to install vertical loops. Horizontal loops are less if you have
the room.

If you have both heat/cool needs you're going to need to add an A/C to
a gas anyway.
If your WaterFurnace has provided both heat/cool for 17 yrs (so far!!)
without major problems you had a well done installation. And today's
units from most brands use scroll compressors which are much better;
much quieter, more efficient, longer life. Copeland Scroll compressors
are the best. There's even 2-stage compressors that are even more
efficient and require less cycling.

WaterFurnace is by far the leader in GSHP installations. Carrier is a
long established premium brand in HVAC. If your install guy recommends
a Carrier GSHP, definitely consider it. Get several bids, however.
Sounds like your install guy has provided good service to you over the
years. Most of the problems in GSHP systems are installation related.
He may be worth an extra $1-2K for his expertise and peace of mind.

Also, you can size the GSHP to provide much of the hot water needs,
especially in the summer with a desuperheater recovering the waste heat
from cooling.

wrote:

Hi,

I'm currently running an older (17yrs) Water Furnace water sourced heat
pump off a deep well. This is heating a 3000 sqft property in a colder
climate (Ottawa).

I just had it serviced and the tech (he originally installed this unit)
is suggesting that 15-18yrs is a typical life expectancy of this type
of unit so I'm trying to prepare myself for when it eventually fails.

He's suggesting that this type of heat pump is still the best option
and will offer a long term cost saving but at an upfront cost of appx
CAN$12,000 (OUCH!!!) for a new Carrier unit. Is this price too high?

So, what's the current wisdom, go with another heat pump or switch to
high efficiency gas?