ASHP – Should do better - Must Do Better

richardc1983

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thills

Cardew's (& others) concerns are correct.
In most cases, Air to water HP's aren't going to deliver what they are hyped up to.
When you need them the most, they deliver the least. COP's of low 2's & you will never get a return on your investment, or by the time you do, it will be worn out.

If they genuinely stacked up, then it wouldn't be necessary for grants or subsidies to be provided by the hard taxed majority.

Insulation, should be where grants go. It's the 1st, 2nd & 3rd area to spend money.

[Deleted User]

thills wrote: »

Cardew's (& others) concerns are correct.
In most cases, Air to water HP's aren't going to deliver what they are hyped up to.
When you need them the most, they deliver the least. COP's of low 2's & you will never get a return on your investment, or by the time you do, it will be worn out.

If they genuinely stacked up, then it wouldn't be necessary for grants or subsidies to be provided by the hard taxed majority.

Insulation, should be where grants go. It's the 1st, 2nd & 3rd area to spend money.

Great to hear the opinion of yet another internet expert

TiredGeek

jeepjunkie wrote: »

Great to hear the opinion of yet another internet expert

Unnecessary!
A case of pot - kettle - black methinks.

As an owner of ASHP technology which managed to consume £430 of electric in 30 days heating my house on frost 'stat at 10'c I have a certain amount of knowledge and an opinion. However, my opinion is of no more value than your's and no more than anyone else's either...... I'm not going to criticise anyone because they don't agree with mine, I'll just ignore them, particularly because I know I'm right

Cardew

jeepjunkie wrote: »

Great to hear the opinion of yet another internet expert

Isn't that what we all do to a greater or lesser extent - research on the Internet; years ago we did it in libraries. Indeed you posted this earlier today:

Nibe ASHPs are complete tosh but the GSHPs are ok.

How do you feel qualified to comment(accurately IMO) if it were not gleaned from the internet?

As we have discussed before, you are happy with your system albeit you haven't had it that long. So you were wise, or lucky, or both and seemed to get a satisfactory installation.

Is not the 12 month EST trial of loads of ASHP and GSHP systems an indication of an unsatisfactory situation?

[Deleted User]

Comparing utility bills with my retired parents our ASHP [inc total electric for house] is working out cheaper to run than his new Bosch Worcester condensing GCH. The two properties are similar sized, similar age, same construction, same part of the country, average insulation and both heated to maintain comfortable temps as occupied during the day. Only once you add in his electric bill on top of his gas bill the ASHP is significantly cheaper.

Real life is simpler than the web and I also know a lot of people that work on and install renewables...

I wrote what I did in response to the usual all ASHPs are crap type statement but I also have a lot of sympathy for people with systems that are not installed and spec'd correctly...

The grant thing confused me. I know people who got several £000 towards renewables but we did not as that scheme has been canned for some time. RHI is £850 which is neither here nor there with some vague promise of £x in the future... We bought it for what it is not for any grant, that's what the PV is there for [erm once the dark days of winter are over it might do something noticeable]

The car scrappage scheme had better terms which had a bigger uptake [ok it screwed the second hand market...]

Insulation is good up to a point but you still need to heat your house and if off grid GSHP/ASHP is one of the better ways. What's the other choice.. LPG/oil? Well that would easily burn £300-£400 odd a month if used in the same manner as the ASHP in our current house. Add that up and the ASHP easily pays for itself, quickly...


Apologies if I've been cheeky, again...:)

thills

Well, I didn't claim to be an expert, but I don't work for the HP industry either.
This is I think, a money saving forum? Cardew points out that this isn't a money saving certainty & this is backed up by the bulk of independent research, you see there, I can read, but do admit I'm not certified in it.
It's a technology, it will work for some, but it won't work for most as most UK properties are not suitable.

John_Pierpoint

A heat pump system needs to be designed - the first step is to fully understand the heat loss characteristics of the property. This is not just the thermal rate of loss through the "envelope" plus the rate of air change; it also includes the thermal mass of the building and the thermal gains available through southerly facing windows and the nature of the shading at different times of the year.

Are you going to put the heat into the floor slab(s) during the night using economy 7 ?

Then there is the trade off of oversizing the heat pump versus turning on full price electricity when the outside temperature is below degrees 7 thru minus 5 (take your choice).

Get all these right and your might be on the route to http://www.passivhaus.org.uk/standard.jsp?id=37

However in reality you are only 66% of the way there. Houses are for people. Most people in the UK have a "We are the Masters" attitude to natural resources. Remember those British Gas adverts "Natural Gas the fuel that obeys you". They expect to flick a switch and get instant results (and get very annoyed and frustrated when they cannot). No matter how good the heuristics built into the equipment, tomorrow's weather forecast will never be 100% accurate.
Twiddling with the switches will make the system inherently unstable and the results will be reduced comfort and increased bills.

[I installed my own traditional wet radiator central heating system, using rules of thumb; OK I ended up with a radiator in the sitting room that is almost never needed and having to replace a single radiator with a double in the bedroom in the North East corner of the property (an adjustment that cost me less than £100). You cannot do that with a heat pump system - it is almost all or nothing]

Here is a thread on how not to install an air source heat pump system:
http://forums.moneysavingexpert.com/showthread.php?t=2959648&highlight=nibe

[Deleted User]

A heat pump is money saving to those of us off grid. It is also a very straightforward technology. There is no magic fairy dust involved. As with any heating system you size it to the house and insulate as best you can. Further an exhaust air ASHP is totally different from an air to water unit. The EcoDan has the same boiler controls as most GCH systems, no rocket science there either...

I'm not saying all ASHPs are good. There are units out there that may be good but are so complex no !!!!!! can fully understand them which has a knock on effect when future issues occur.

That's why after careful consideration the choice was narrowed down to Daikin Altherma and Mitsubishi EcoDan but the Mits won due to the heat demand we required.

John_Pierpoint

Probably money saving relative to oil and LPG and plain night storage, when retro fitted; even when fully price electricity has to be used as a top up.

Not not as moneysaving as mains gas condensing boiler or living in a house built to 2020 standards.