Heating

[urmysunshine!]

Hi all
Just wondering if someone can explain to me what a heat pump is and what they cost to run? Are they efective? Just wondering what would be more cost effective....a heat pump or log fire?

[Super_BQ]

A log fire is by far the cheapest form of heating in any house. There simply is no comparison because for most users, they source cheap or free firewood. Now the problem with log fires is virtually all new houses built don't have it due to city fire restrictions (clean air programs).

This means the next best choice is a heat pump (or in overseas terms, air conditioning units). I won't go into the details of how they work but they are far more efficient at producing heat than conventional plug in heaters. The heat pump extracts heat from outside of the house and pumps it inside. This process is where the efficiency gain occurs where it can typically be 2:1 (depending on outside temperatures). Meaning, the heat pump unit itself can draw 1kW of electricity but in effect, produce 2kW of heating inside the house. Compare that to a plug in electric heater that would draw 2kW of electricity and only produce 2kW of actual heating.

Now the tricky part is, heat pumps may not save you electricity at all. The reason is that although they produce more heat per kW used, users tend to expect more heating from them than they normally would. Meaning they expect the whole room heated to room temperature (due to how they blow hot air around) whereas say, an oil filled heater (with the fins), a person may be happy enough sitting next to it to keep warm and not bothered to wanting to heat the whole room. In this sense, a heat pump will cost you more $ to operate if you expect full room temperature heating.

[Nienke]

I have two mitsubishi heatpumps in my house, when heating in winter (all day long) they don't raise my electricity bill by much. They are expensive to install though, but very cheap to run.

[Jo Jo]

Now the problem with log fires is virtually all new houses built don't have it due to city fire restrictions (clean air programs).

Virtually all new houses where? In Christchurch? In Canterbury? In New Zealand as a whole?

[benandclare]

This link should help you.

http://www.heatsmart.co.nz/Central+H...mparisons.html

We use a multifuel burner as our main source of heating which also runs hot water radiators as it's a wetback. If, as SBQ says, we couldn't source cheap wood we would have installed a diesel boiler to run the radiators and in the future we may well add one

[Super_BQ]

Virtually all new houses where? In Christchurch? In Canterbury? In New Zealand as a whole?

http://www.mfe.govt.nz/laws/standard...rner-faqs.html

This provides some answer on a national standards level - it's quite clear that as a country on a whole, clean air policy is a serious issue. To the point that in some city townships, they will eventually BAN the use of wood burning.

I don't have the time to go through all the major cities in NZ but we know for sure Christchurch does ban use of solid wood burners in certain areas:

http://www.ecan.govt.nz/advice/your-...istchurch.aspx

In the Clean Air Zone 1 - it states that existing houses with no previous solid wood burner will not be allowed to have one installed. Well technically you could have one but it requires a 'resource consent' and I speak from experience, getting a resource consent is no easy feat. In fact, it's nearly impossible because it requires the approval of all the neighbouring houses. But there's something more critical to why most newly built houses don't have them.

Now i'm speaking for Christchurch. All submitted house plans must provide means of heating in the house. When it's shown that the primary source of heat is a solid wood burner (not pellet burners), they tend to get real fussy. The reason is that eventually, all sources of log wood burning will be banned and that a house that relies on wood burning, would mean serious troubles in it's design. Look at all the state built houses for example. Although many of them have had their primary source of heating converted to using heat pumps, majority of them claim the retrofit is too costly. Like you just can't put in a heat pump and get results - there has to be an insulation program to go with it. Big $$$ to a person that may not be living in a state house for long (or to reap any benefit).

Actually the difficulty in getting resource consent with CCC for a wood burner has come to the point that major home builders don't bother. If you look in the archives in this forum, i'm sure i've mentioned the problem my uncle had when trying to get approval for a wood burner in his house. Despite the wood burner was an Ecan approved model - CCC rejected the application based on not being able to show how much "particulate emissions" on the section he was building. Think it's simple? Just off the head he needed climate data for wind and rain and had to be computed to the point that a university prof would have to make up the report.

http://www.nelsoncitycouncil.co.nz/enclosed-burners/

Looks like Nelson is serious with air care. After the end of this year - firewood burning BANNED!

[Super_BQ]

good link benandclare. I especially like the last illustration

[Dell]

What kind of wood is commonly used for firewood? I'm guessing macrocarpa?
How much do you pay for it and is it easy to find someone selling it? Thanks.

[urmysunshine!]

Thanks for all the info guys realize now that in Oz we have "heat pumps"... Just call them reverse cycle air cons! I had all sort of weird ideas as to what a heat pump was!

[Super_BQ]

What kind of wood is commonly used for firewood? I'm guessing macrocarpa?
How much do you pay for it and is it easy to find someone selling it? Thanks.

Any wood that is not chemically treated. This includes cardboard, paper, or anything that can burn. During the construction of our house, we often had people snooping in the large rubbish bins on site to take any off cuts to burn. The green or pink treated wood they do not take - maybe because the chemicals it release when it's burned is toxic. So in this sense, free

I can't put a price on a cord of wood but i'm sure that if you had to buy it, it would still cost a lot less than solely using electric to heat a house.