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Hi Romaron
I don't have access to any useful data sheets giving the radiator size reqs. But its a rather simple equation sq.m x heat loss assuming you are running off thermostats.
For 500sqm house built to modern building regs you have an estimated heat loss of ca. 20 -25kW. You cant start a 25kW system on single phase electricity, so you would need 2 x12kW units with staggering, so they don't start at the same time. Back in the day that would have cost ca. 25k. You would need a ca. 1m3 heat sink at least for a dx system. Good luck.
Fantastic reply Dreamer - Thank you. You are an asset to this message board. I already have a pressurised Megaflo cylinder. May I be cheeky and ask what size air-source heat pump for a 500 sq.m would require and price. Are there any data sheet out there giving the radiator size requirement for a room?
I'll level with you. In the 60's my father had a coal round and his own lorry. We also had a cash operated electricity meter. The cooking gas was described as "coal gas" and prededed North Sea gas. We even had racing pigeons and Great North Road racing started at Peterborough and worked up weekly to Fraserburgh, Thurso and Lerwick through Selby.
romaron
She went for the High Temp Daiken that doesn't require change of rads As I say it works but expensive to run. Salesmen quote 4.5 cop but also quote high temp does not require Rad upgrade the two don't go together.
Hi Romaron andTigar
I don't disagree with any of your comments re builders cutting corners, nor that older houses are leaky. Firstly i will level with you, I am Swedish but live in the UK. I have a dx system and my family used to sell HPs 15-20 years ago. To really answer your questions would take an age, but there are a couple of things to understand about heat pumps. There are your traditional ground source HPs (pipes in the ground or borehole). If installed correctly (i.e no shortcuts on laying the pipes) they are very effective in colder climates, but usually only heats water to ca. 35'C. They last forever and the only part you need to replace is the compressor when it goes after ca. 40k hours. You then have the dual air to air HP's that can be used as both AC in summer and Heaters in the winter. Very efficient provided your outside air temperature does not go below zero for more than a few days a year . You then have the more modern Airsource HPs that heat water. These come in two formats dx (direct exchange) which operate best if you have a proper heat sink /store (usually ca. .5m3) or normal system that have a heat exchanger and no heat sink. In the UK you don't get many dx systems, as they require more investment (heat storage tank) and also requires not only a plumber but also a refrigeration engineer to install. Normal non DX systems come pre-gassed and dont need to be installed by a refrigeration engineer. The big difference is that a dx system also provides you with your domestic hot water (at 85'C which can only be accumulated in the heat sink). Essentially water forthe heating comes out of the bottom half of the tank (stratification) and the domstic hot water comes from the super heated top half of the tank. Before someone jumps on me and says that is not possible, it is, but the domestic water is obviously not mixed with the central heating water, but is heated from the superheated water through a normal coil. There is obviously a limit to how much hot water comes out as you will drain the heatsink if you are using a lot of domestic hot water. Average house 180sq.m built to modern spec should have a heat loss of ca. 50w/sq.m .= 9kW need. HPs cost ca. £1k /kW. A prudent architect would put in a 12kW. Your system would therefore cost somewhere around £12k. it will be 9k for a normal ground source HP and more like 13k for an airsource DX system. Payback will be between 7-12 years. The more heat you need/use the quicker the payback. I am not looking to argue with anyone, but simply try to give some insight into my own personal experience with and understanding of an airsource dx heatpump installed in the UK.
Dreamer
Thanks Tigar. "cost above what her old oil system did" and that would have been expensive. If I had oil I'd definitely consider a heat pump. You use yours as back-up but I'm guessing it wouldn't run the heating alone without the gas in winter?
I'm surprised that she reckons 2 powermatics would be cheaper than her heat pump. Not trying to deprecate heat pumps but they're not as simple or economic as the Government or salesmen are saying.
This is what we're fighting against as shareholders here. The economics are massively in our favour but public opinion isn't. My argument is that it is all hot air and promises. There isn't a chance in hell that they will meet targets without enormous subsidies. Energy bill payers have votes. The Government knows this so hide the truth.
Hi romaron
I have a powrmatic vision 3.1kw through wall heat pump it is used as aircon in summer and heating when chilly and extra back up to gas heating when cold. As air to air it is absolutely brilliant brings cold room up to 24degre's in minutes and is very cheap to run. My sister has full Daikin high temp heat pump instalation with standard rads it works fine but cost above what her old oil system did. She has fitted a powrmatic and feels that two would keep bungalow warm a lot cheaper than her air to water neat pump. You only have to look in shops and pubs to see that air to air works I am convinced it would be a lot cheaper and more efficient to concentrate on heating the air than water in rads. And divert spare power from Solar panels to heat your hot water tank it cut my gas bill buy a third.
I'll head anything not directly EnQuest related Off Topic (O/T). It seldom affects the price and will only interest a few of you so the majority can safely ignore.
Hi Dreamer81 re your 12.01 post. I'm hoping you know more than your post because I have a questions. I was involved with heat pumps a decade or so ago and at the time there weren't many to choose from and the debate was about Mitsubishi boilers. Several heating engineers were complaining about the multiples of converting electricity to home heating. There were manufacturer's claims of up to 4 X but they were getting barely 2X. I'm sure there have been improvements since but I recently tried to get the optimum performance figures for radiator size per room needed for myself. I want the figures unadorned and it looks like I'll need a F.O.I. request to get them (joking). My point is that there are elements of thermal mass involved and for optimum performance you need tightness, insulation and the correct heat transmitters to get maximum performance. A lot of companies are saying that as many homes have oversized radiators anyway so you might be able to get away with existing rads. That is salesman talk and in a worst scenario you might need the heat pump on 24/7. A bit like when car manufacturers quoted mileage for their models e.g. driving at no more than 30 mph, coasting downhill, little braking and plenty of anticipation. Do you know the optimum radiator size for space heating by heat pump?
An inefficient heat pump won't compete with fossil fuels and most of our properties are old and leaky. Even an efficient one requires further efficiencies in retro fitting and does anybody really trust builders at the lower end of housing to understand or not cut corners regarding installations. I'm not even convinced they'll do new-bui
I read that heat pumps are successful in Sweden but they have always beehn ahead of us in tightness and insulation as it gets proper cold out there. They are anyway a strange race as they enjoy rolling around naked in the snow and whipping themselves with birch twigs (*could be a Therapist connection) and would happily spend hours sitting on an ice floe not catching anything.
1kW of electricity is used to extract 2.2kW of renewable heat energy from the air and produce a higghly efficient output of 3.2kW heat. So 3 times as much energy as it uses compared to a traditional boiler which turns 92% of the fuel it uses into energy. Pretending cost doesn't come into it is puerile and disingenuous. That is what this present Government is doing.
*there was a Radio4 programme today c.12.30 with 3 users asked their views. One lived in a rural area and replaced an oil boiler. A pensioner in a 2 bed bungalow who did it to save her grandchild's future and complained about how long it took to become "efficient" and the cost of £12k. Both brought in the grants and their "persuasive" effect. It didn't come over as wholehearted support. The 3rd seemed h