Ballynoes

Sorry I meant my electricity usage drop by half as soon as the heating goes off. I use roughly 30Kw/Day during winter and once the heating is off I use around 15Kw/Day, This might be high compared to some but there are multiple other factors in my daily Kw usage not just home heating and DHW. Still working on the heating demands bit, hence the question, and still getting used to the ASHP, just had 1 winter with it . But compared to £2000 each year to heat the old (now demolished cottage) I can't complain too much.

Thanks all, just had the one winter with the ASHP so still getting to grips with it. Might not plunge into the Economy 7 tariff just yet then. as SteamyTea says the heating is off now and only DHW which is timed the same every day all year, so I can get good base figures to start. I do know from my electricity readings my usage drops by half or so as soon as the heating goes off. Always learning..

Interesting JohnMo, thanks for taking the time to answer. Still getting used to an ASHP, but would flow temps in the 20's actually produce "noticeable" heating. Might try that as well. The house is well insulated so it doesn't need much to keep it warm, I guess I am still in the oil boiler mind set, where the radiators had to be in the 60 degree range to heat the old house. Trial and error I guess. Many Thanks.

ASHP, what’s the best way. I guess this is the question most asked about ASHP’s how and when to have it on. So the house is built and we have been in just over 12 months now. So far the ASHP seams like a good choice. However I was just wondering if anyone on here can shed light on my question. Do I leave it on all the time or switch it on and off. I have A Mitsubishi Ecodan 8Kw heat pump, with a storage cylinder for DHW and UFH throughout, all floors are tiled. The house is really well insulated, and very air tight, no drafts, like the old cottage. Last year the heating was on from say October till April, we don’t need any heating out with that usually, as the glass wall lets in lots of thermal heat as soon as the sun shines. My rooms are controlled by thermostats in each zone, no timers built in, it’s either calling for heat or not. Played around with-it last year and the option I ended up using was to have the flow temperature of the UFH set at 45 degrees. Heating came on at say 3am till 9am. This put heat into the floors and it radiated up during the day, house was fine no issues. Same thing the next day. Then thought about an Economy 7 tariff as I have my heating is on during the night. Hot water is not an issue. To keep the cylinder full of hot water when the heating is off, the ASHP is only working about 5% of the week. Hot water on from say 7am until 10pm. Obviously the hotter the flow temperature the more the pump is working and the more KW’s I use. I have been investigating the best way to get the most out of the ASHP, and most sites I look at say to set the flow temp to 38 degrees, but leave it on all the time. That’s my conundrum. Obviously not having tried that I have no stats for electricity usage, and it’s all about the KW now the prices have gone through the roof. Most of the recommendations to leave it on all the time suggest turning the temp down at night, but I can’t do that with my thermostats. Is it just a matter of trying it on 24/7 at the lower temperature, but I have no need for rooms temps of 22 through the night. ?? So I was just wondering if the collective geniuses on here could shed any light as to options worth investigating. Many Thanks in advance.

Just as a side question, how noisy are ASHP's, as I was hoping to site it outside the house, on the south side, as this gets most of the sun and warmth. Any thoughts. Edited, sorry should have said directly outside the house.

Thanks, much appreciated.

I'm interested ProDave how you're 4Kw solar system only cost £1500, I have been quoted close to £6500, which makes it un-viable, At £1500, I would jump at it, did you do it yourself. If I can get the equipment and get the builder to install it whilst he is building the house it might be an option. So far a 500w panel comes in at £400 and I need 8, pus the inventor.

Hi, thanks for the replies, I suspect ScottishJohn has hit the nail on the head, with people fed up paying for Oil heating and persuaded to fit an ASHP by a salesman, then being surprised that it costs a fortune to heat their still old drafty house. Our new build will be well insulated draft free and have good insulation figures, so I suspect it won't use £1250 per year to heat, as that is what I pay on Oil for my old drafty soon to be demolished house.... can't wait. But I'm still struggling to justify solar panels, so far it will take me 23 years to get a return for a 4Kwh array fitted. No wonder no one fits them any more.

Hi, just looking for some real advice. We are soon to start our build, and I hear horror stories, from those who have not built, about Air Source heat pumps, running away with electricity use. Is this real life or scare mongering, most of those who say this do not have a heat pump, but " know someone who knew someone", you get the drift. So my question is, for those who have fitted an Air Source heat pump, did it run away with electricity or not. I know we will have additional electricity costs, because of the heat pump but we are currently using oil, and I calculate we would need to use an additional 9500KWh each year to be "out of pocket", that's roughly an additional £103 per month of electricity, on top of our current use. Bearing in mind our new house will have an Air Source heat pump, underfloor heating, and will have U-values of 0.17 W/m2K, according to the spec. I have tried to justify solar panels as well but the sums just don't add up either, taking roughly 23 years to get my investment back. Thanks in advance.

This looks promising. http://www.chelmerheating.co.uk/self-build/thermal-store-and-buffer-cylinders/thermal-store-heat-bank-cylinders.html

I wish we had gas, but live in the country, so don't even have sewage, or decent broadband, but that's the price you pay for piece and quiet surrounded by your own fields... not complaining though. ? I still find it difficult to comprehend that you cant "feed" a hot water cylinder with two different form of heating, after all I was under the impression that you had to occasionally heat the hot water tank to a certain temperature, to make sure certain bacteria don't thrive... or is that another myth. ?

Hi ProDave, I was thinking that in the summer months, with a fully insulated house, the ASHP would provide sufficient hot water, and only be running at a small percentage of its capacity, as it will probably not be heating the UFH, I just thought that in the winter when UFH demands are higher, I can supplement the DHW, with the log Burner. After all, if I am building from scratch now is the time to install it all, even if it only gets used occasionally, as the Log Burner will essential be fed by free timber. Just my thoughts.

I was think along the lines of ProDave's answer, in that why pay for electricity to run the ASHP, to heat a tank of hot water in the winter, when I can get free wood to run a Log Burner, which will heat the hot water and throw out extra heat into the whole house. I am surrounded by woods and live opposite a sawmill, and each year I burn excess wood in the open just to get rid of it. Yes the ASHP will come on automatically, like "central heating", when we need it, but I can "turn it off" when the log burner is producing what will effectively be free heat. Very interesting replies all the same.

I'm slightly disappointed that you can’t simply connect a wood burning stove, to the hot water cylinder which the ASHP will also heat. Back when I was a lad, we had an immersion heated water cylinder ALSO connected to the coal fire back boiler, so when the fire was lit, no need for the electric immersion heater. This sounds like a step backwards ?? To answer the points above, this is a new build, fully insulated with an ASHP and underfloor heating. I was only looking to fit a log burner for those long cold evenings. Also during these times in winter the ASHP would have to work overtime to heat the water as well, when it is least efficient, due to the ambient temperature. The log burner I hoped would supplement the water heating during these times, and just leave the ASHP to deal with the UFH. Am I missing something…. probably.

As the house is being built from scratch, I can have as much space as I need, insulation levels will be "over the top", as I have spent 30 years in a cold drafty 200 year old house, hence the new build. I checked and there are no smoke control zones anywhere near us, thankfully.

Sorry if this is in the wrong topic, but I can't quite see where it fits. We are currently drawing up the design for the new build, and we plan to install a wood burner stove, as we only work 3 days a week, so have the luxury of being at home for 4 days. Underfloor heating will take care of the general heat, bit I wanted a wood burner for those toasty lazy evenings. The question is, how easy is it to connect a wood burner to a hot water storage tank, as hot water will probably be our biggest use of energy. Not really going the Solar thermal or PV route as I don’t think I will get my investment back for quite some time. The wood burner is designed in so I’m sure it won’t take muck to hook it up the hot water store. Or are there issues I haven’t thought about with this setup. Will be using an ASHP also, Thanks in advance.

Hi This is possibly a good solution, as I intend to purchase items like the kitchen and bathrooms of our choice and get the contractor to fit them. So asking them to fit a solar system will not be that much more different, esp if it is specified in the contract terms. Hadn't thought of that way. I would imagine I will be "forced" by planning to install slates of some description as all the other properties around have slate roofs, probably Spanish slates. Thanks.

I believe there is an option to charge batteries, and through an inverter reuse the power that way. Has anyone come across this option, and is it viable for domestic use.

From my perspective I am slightly different in that I am not really self building, I plan to hand the drawings to my main contractor and have it all done for me. The PV panels are just an option if I think they will be cost effective, so buying from eBay, whilst a good idea, I will have to have mine installed by a certified installer etc, if I intend to pick up any type of FIT or Smart Export Guarantee, as it looks like it will be called. I would therefore need to get my investment back in say 10-15 years, but all the figures I have so far are considerably longer than this, so it's still a decision to be made. While I am keen to use renewable energy, and save the planet so to speak, a 30-40 year return on my investment is not that attractive at this stage

This is all very confusing, I was doing a bit digging yesterday, and the energy saving trust website came up with a installation cost of just over £6000 for a 4Kw system, fitted. (I'm not interested in a DIY fit at present) They estimate I would save was just shy of £150 per year, so doing basic maths it would take me 40 to get my money back... I won't be on this planet in 40 years time... Since there are no more feed in tariffs, I really don't see the point..... or am I missing something ?

I have just read that this scheme closes on the 31st March 2019... missed the boat as they say. I don't think they will be worth the investment in this case ?

I was just wondering if PV panels were worth the investment. Though I would ask those who have already. I am planning to put an ASHP in which will run the underfloor heating. But the feed in tariffs are not that good these days, so my investment will take quite some time to pay me back (not sure how long these days). So the question is are they really worth it, brand new build so now would be the time to do it. AND OR would I better off installing thermal solar for my hot water instead. Thanks All

All very interesting, I just assumed GSHP's were better than ASHP. Not going to be a huge house to heat, and we are planning a log burner for those cold winter nights to cook us. As for electricity, well, when your wife has 18 flood lights round her outdoor riding school, and a 9Kw shower...just for the horses.... you get the idea. About 6 miles from Dunkeld, but in the countryside so we get no shelter from anyone.

Hi Dave, thanks for the reply, we are nearer Dunkeld, so compared to to you not "really" in the Highlands, but since we are on our own in the country, the weather can get pretty chilly in the winter, and when it snows it snows, so we can get temperatures down as far as -15 because of our location. My thoughts were to install a GSHP as we have 10 acres, so ground loops are not an issue, I just thought naively an ASHP was less able to heat the house in winter, but since joining here, I am having second thoughts. The house will be built to 0.1 U value, that's a given, as our old stone cottage is 200 years old and costs a fortune to heat, and when the wind blows it just strips the heat from it. Could someone explain what you mean by "defrost" is this because the ASHP is working overtime and causes itself to ice up... I assume then it takes extra energy to defrost itself before producing heat ?? As you say with a well insulated house it will probably stay "relatively warm" overnight so in the mornings require less heat to bring it up to a comfortable temperature. Is it best to go for an ASHP which is Over specked, just in case or not necessary. Thanks Again.

This is slightly concerning as I said we live in Highland Scotland... renowned for its, cold wet winters, this I assume as you say can freeze on the condenser. Maybe I need to read more about ASHP's before making my decision. Any recommended sites to visit...