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dpack
Joined: 02 Jul 2005 Posts: 46220 Location: yes
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NorthernMonkeyGirl
Joined: 10 Apr 2011 Posts: 4630 Location: Peeping over your shoulder
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Posted: Thu Aug 04, 22 6:26 pm Post subject: |
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NorthernMonkeyGirl wrote: |
I came across some heat pumps that were suspiciously cheap (£700 plus installation) given the costs for a full system (the ones eligible for the £5000 Boiler Upgrade Scheme).
I was less suspicious when I looked at them as a standalone air conditioner unit that happened to be reversible.
I'm wondering if - with insulation work etc - one standalone heat pump would suffice for most days in the year, leaving the gas central heating to take over for that odd week or two when things get grim.
I don't really know how to calculate and compare cost per degree C increase?
I do like this youtube channel though - in terms of helping me understand how a heat pump claims to be so much more efficient - it's because you're powering a compressor rather than making a wire glow red hot.
https://www.youtube.com/watch?v=43XKfuptnik |
So, pour a glass of your preferred beverage and behold my Crap Maths With Assumptions
- assume 30 kW gas boiler
this converts to around 102300 BTU
- this says 24000 BTU at 1.9kW
https://www.appliancesdirect.co.uk/p/iqool24/electriq-iqool24-air-conditioner
So, let's say this particular ASHP gives off a quarter of the heat energy of the gas boiler. Ignore the cooling function for now.
My current tariff is 29.6p / kWh electricity and 7.4p / kWh gas. Ignore the standing charges.
So, an hour of ASHP would be 1.9 * 29.6 = 56.24p
An hour of gas boiler would be 30 * 7.4 = 222p
222 / 56.24 = 3.9 i.e ASHP is a quarter of the price of the gas
Which implies the cost per BTU is very roughly the same at this point.
So the questions are
- can the slow and steady ASHP maintain a suitable temperature?
- (noting that if only the gas boiler can reach the desired temp, you will be losing that heat and paying for it anyway, so would benefit from insulating)
- noise
- maintenance commitment and costs (and risks of poor maintenance, I guess)
- future utilities price changes
- future installation of domestic solar panels?
- better to spend money on insulating?
- worth having for the bonus air con?
Air-to-water heat pumps are a different beast again, with the probable need for bigger radiators (or switch to underfloor heating or something).
My two-doors-down neighbour has a heat pump of some variety and I occasionally notice it, but not really.
Please feel free to correct the maths! |
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Mistress Rose
Joined: 21 Jul 2011 Posts: 15972
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Slim
Joined: 05 Mar 2006 Posts: 6612 Location: New England (In the US of A)
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Slim
Joined: 05 Mar 2006 Posts: 6612 Location: New England (In the US of A)
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Nicky cigreen
Joined: 25 Jun 2007 Posts: 9881 Location: Devon, uk
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Ty Gwyn
Joined: 22 Sep 2010 Posts: 4613 Location: Lampeter
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dpack
Joined: 02 Jul 2005 Posts: 46220 Location: yes
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Mistress Rose
Joined: 21 Jul 2011 Posts: 15972
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Slim
Joined: 05 Mar 2006 Posts: 6612 Location: New England (In the US of A)
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Posted: Sat Aug 06, 22 9:44 am Post subject: |
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Around here the valuable tinder goes to lumber, etc, some lower quality hardwood go to cordwood, and in big operations the slash and low quality stuff go to wood pellets, and occasionally chips. With of course a diversity in harvest styles between different land managers. My neighbor let a company come and clear out any trees of value, and huge swaths of low quality stuff as well via feller bunchers. I haven't walked over there in a couple years, so it would be interesting to see how the regrowth looks. While the harvest was dramatic, they did at least leave lots of slash down on the ground, and lots of young trees for regrowth.
The folks who owned our land before us have clearly had it logged, but very selectively, likely via skid steer, so the impact has been less, and we definitely still have some 100+ year old oaks, pines and hemlocks.
Plantation style forestry was tried in this region on small scales about 100 years ago, and you can still see some of them if you pay attention looking for straight rows, but they're very rare up here. They didn't really make sense for our climate, geography, etc, so most of the region is natural regrowth. |
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Nicky cigreen
Joined: 25 Jun 2007 Posts: 9881 Location: Devon, uk
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Mistress Rose
Joined: 21 Jul 2011 Posts: 15972
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Posted: Sun Aug 07, 22 8:53 am Post subject: |
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Slim, if there are big parcels a lot goes to the sawmills, but it is uneconomic for small parcels. There is also very little coherent thinking on timber here either. Our beech plantation was put in about 1969. It has a final felling date of about 2049-69, and it has already been repurposed twice since planting. It was intended for the pulp mills, but we don't have any taking virgin hardwood now. We repurposed it for firewood, but that is currently 'evil' so we are repurposing again for charcoal. Sadly most of it isn't of good enough form for sawmilling, but any good trunks may go that way in our own sawmill.
Most of our wood is natural woodland and we get a variety of species out of that for a lot of different uses. It has been managed for possibly millennia though, as our part of the UK was inhabited virtually since man got this far north. There have been stone age artifacts found not far away, and we have Bronze Age field systems and tumuli under the woods, and Saxon boundary ditches, About 2000 BC and from about 400 AD respectively.
Nicky, yes, air conditioning can be a pain, as can places built for a specific climate. I was in Avignon one autumn on business, and it was so cold at night I had to wear a jumper in bed. |
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NorthernMonkeyGirl
Joined: 10 Apr 2011 Posts: 4630 Location: Peeping over your shoulder
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waerloga
Joined: 11 Sep 2011 Posts: 9
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dpack
Joined: 02 Jul 2005 Posts: 46220 Location: yes
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