Who knows about heat pumps?

[Genestho]

I have an HRV which I had installed 3 winters ago and two heat pumps; Panasonic 7or 8? kw inverter (a bit noisy) and a fujitsu 4 or 5 kw? (quiet) inverter installed over the next two consecutive winters, together the whole system is fantastic, HRV keeps the home dry so it takes less energy to heat the air.

The HRV immediatly removed condensation off windows etc, have never had to wipe joinery again!!

Home is fully insulated, under a third of the home is double glazed..just have to regularly wash the outside systems with fresh water and change filters.

I did look at a log fire but the whole rigmerole really wasn't appealing, haven't had a power outage in winter...(yet - touch wood - hah)

Power bills are excessive in winter though.. but equate that with alternative heating, less colds/doctors bills and perscriptions, probably evens itself out..

[crazyhorse]

Looks like I sold me house. Now I hafta find somewhere else to live. The one I am looking at has no heating but looks a prime candidate for a heat pump - if I can get it cheap enough (the house that is, not the heat pump).

Since I know eff all about heat pumps I thought I wold consult that repository of all knowledge and enlightenment, KIWIBIKER!

So tell me, good people, what I need to know.

Are their differences between brands?

Are there good and bad installers to deal with? (In or around The Tron)

How wildly do prices vary?

What traps are there for the unwary?

How do we know if a quote is realistic or not?

Is there a formula for calculating how many gazillawatts we need?

Thanks in advance for your input. Most useful answer will be showered with bling...

I put in a Daikin - Its a big one with an inverter. Got a excellent deal - bout $2800 and goes really good - cools the house down real quick, and heats it up in winter just the same. Have hardly noticed a difference to my power account. But my home is only about 6 years old, so should be well insulated too.

I swear by this one. Good luck John

[BMWST?]

fact.heat pumps are efficient,you get more heat out of em than the electricicty you put in.They are the most efficient form of heating.The only way you can compete with a heat pump for heating is a pellet burner,or if your firewood for a log burner is free or cheap(consumer).The reason heat pumps become expensive is that people change their habits.Ie set it to come on in the morning and or evening,and start using it to cool as well.
They cool or heat by blowing heated or cooled air.Be careful with siting the indoor unit some people dont like moving air near them.
A ventilation system is a good purchase,the day after we put ours in the condensation on the windows was gone.You can get ventilation systems that can transfer heat around the house and also get a system to bring air directly from outside to help cool the house in summer.The ventilation systems make our house hotter in summer blowing the 28 c plus air form the roof space.It shuts down at 28 so will be looking at the outside air option.
As an aside i would not buy a flat roof house.one day it WILL leak and as you say you cant really fit insulation or a hrv type system.
The classic house shape has been developed cos it works.....
/rant off

[Mully]

My (sort-of) cousin owns a company in Auckland that does HVAC and whatnot.

He's getting us a full-noise ducted bells-and-whistles system (at COST!!) when we build, later this year.

Along with high-spec insulation, double glazing and whatnot, we should be sweeeeet.

His advice:
Any of the Japanese brands are great - anything else be wary of.
You need (as mentioned) good insulation. He was ambivalent about HRV and whatnot, but admitted they were a great retrofit to an existing house.

[porky]

They are in fact a reversable "fridge" with a fan. This principle is called the mechanical refrigeration cycle. An evaporator, condenser and compressor and a reversing valve with something like R22 (monochloridifluoromethane.... i think thats what the shits called but are prepared to stand corrected) coursing thru its veins, changing state from a liquid to gas and back again. To maximise efficiency and lower cost in the heating the installation of heat sinks give a better bang for ya buck. Design is important or you will chuck away good money. There is a formula Kw per sqm, but as mentioned insulation, not just the pink shit in the walls and roof plays a part as does glazing area.... especially south facing, floor material, carpet stud height etc. the best system is the commercial ventilation and air conditioning system that conditions part of the stale air with a quantity of fresh and modifys the humidity. These simply suc and blo, as the temp rises moisture is held in suspension and as the air cool forms as condensation. Buy a big fuck off log burner and leave the window open, heat and ventilation. Shagging in front of the heat pump dosnt really cut it.

[Grumph]

[QUOTE=porky; Shagging in front of the heat pump dosnt really cut it.[/QUOTE]

Dead right mate....

location in NZ has a lot to do with how happy you'll be with a heat pump. Further South or higher you go the harder the HP has to work hence the higher the cost of running. Most of ChCh is marginal cost/efficiency unless you're lucky enough to have a very well insulated house - and HD Case is the only person I've heard of running one in the summer down here.
If we come out of the quake washup with a new house it'll have log burners fer sure.

[porky]

Dead right mate....

location in NZ has a lot to do with how happy you'll be with a heat pump. Further South or higher you go the harder the HP has to work hence the higher the cost of running. Most of ChCh is marginal cost/efficiency unless you're lucky enough to have a very well insulated house - and HD Case is the only person I've heard of running one in the summer down here.
If we come out of the quake washup with a new house it'll have log burners fer sure.

And if you do, go for a 22kw unit ( for approx 200sqm house) with a 4kw coil (back boiler ) hooked into a Harris or similar mains pressure HW cylinder. They are s/s liner with a calorifier inside (the old wet back system up graded to mains pressure but with a closed loop- heating water dosnt end up at the tap- just goes from fire to hw vessel and back again at low pressure, sort of the same as the commercial systems you would find in places like hospitals.) Most efficient use of energy. One day i will get anal and sit down and prove with numbers that the electric string isnt that flash for heating.... you pay for conveience.... bit like cell phones. Marketing is king...... Only prob is, chch probably wants the eco flue etc under their District plan unless you are on a 2+ ha property. You will need to check it out.

[steve_t]

One day i will get anal ... You will need to check it out.