Heat Pumps - post here.

redmagic68

It depends greatly on your electricity tariffs. I and others run our hp on night rate electricity pretty much exclusively. I have a day/night meter with a substantially cheaper night rate. While I may use a little more annually in terms of kW/year the cost of these units is less than running it on day units therefore saving money, also this tends to be greener electricity so better overall for the environment. I build up a bank of heat over night and the floor releases it throughout the day and evening time. You have to know your own house to know what set temp works for you or it can be too hot during the day.

https://www.boards.ie/discussion/comment/119937352#Comment_119937352

In The summer months say from April to mid end of October we have no space heating requirement just limited dhw.

THE ALM

Looking a bit of advice/help.

Final big job is replacing the existing, 16 year old Warmflow, oil boiler. Will get this winter out of it so a job for the spring/early summer.

Getting my head round figures for heat loss and radiator sizing so we can get a rough price for the job and that it is the right way to go. Wanting to get away from the oil and feel an air source heat pump is our best option.

2006 Bungalow, raft foundation so UFH won't be an option, walls pumped with Walltite, have added extra attic insulation and the windows and doors have all just been upgraded to composite and triple glazed. House BER after solar pv and before windows and doors was a B2. Have spoken to our BER guy and forwarded the updated specs for doors and windows so waiting to hear where we are at now.

Having spoken to him he feels confident of getting us to <2 for the heat pump grant and I will be scheduling a HLI and airtightness test. I have been replacing all the in-ceiling spotlights (draughty buggers) so feel we have a generally good airtightness.

Working with the seai heat loss calculator I am getting a figure of 9kW. Does this figure seem correct and does this then equate to a heat pump in the 9kW range? I have attached a sample room to see if my inputs seem correct. U-Values are from either the seai or provided from specs I have been given

In terms of radiator sizing I am working out that we have an output currently of 16.4Kw, mostly made up of k2 radiators with a few k1's. Again, would this figure seem correct and how does this figure then relate back to the heat loss calculation.

If anyone can recommend a good heating engineer, installers in the midlands/south Roscommon area that would be great, pm's welcome.

Thanks as always for the help/steer with this.

podge3

https://www.boards.ie/discussion/comment/119937797#Comment_119937797

I should probably have mentioned I have radiators, not UFH. So far, running the heating all night downstairs seems to be working for me.

DC999

https://www.boards.ie/discussion/comment/119938631#Comment_119938631

What are you replacing the 'in-ceiling spotlights (draughty buggers)' with? We have them and so do folks and they poor in cold air in their house (under 2 flat roof extensions).

THE ALM

https://www.boards.ie/discussion/comment/119939055#Comment_119939055

Between the kitchen, dining and living area we replaced 28 spotlights which voided into the attic space. It was right cold air coming down through these and a pig of a job filling the holes, sanding, filling, sanding.... I have 5 in the bathroom to finish and that will be the end of them.

For the living and dining areas I made two oak long strip lights and then for the kitchen I used a surface mounted track with dimmable adjustable spots.

BoardsMember

Is there not something a bit backward in using a heat pump only at night with night rates? Feels a bit like the old days with storage heaters that only come on at night. I get that this is the cheapest way to run it, but is the thermal mass not cooling down by late afternoon when the temp is dropping?

redmagic68

Hasn’t been my experience to date. Heated the bedrooms to 20c at 7 this morning. They’re sitting at 18.7 now.

Living area to 24c at 7 it’s sitting at 21.5c but we had a lot of people moving through the house today so doors open heat out etc as we had people working.

https://www.boards.ie/discussion/comment/119941039#Comment_119941039

it’s a choice isn’t it really, people do what’s best for them. Once my solar system and batteries are rocking I’ll run my heat pump to boost in the afternoon if required as I’ll use load shifting to the battery

in terms of the energy used night rate electricity is cheaper and lower in carbon due to wind at night. Can really only be beaten by making your own. Regardless the less you use day time, the better for the grid, the environment and your pocket. Lastly a large concrete slab is basically a storage heater I don’t regard it as backward

Mr Q

https://www.boards.ie/discussion/comment/119941881#Comment_119941881

It really will vary by person and their setup. I would wake up if the bedroom ever got to 20c due to it being too warm so don't tend to heat it overnight.

I would definitely never heat the house to anywhere near 24c. But what you are you doing might cost less overall to run if your on a reasonable night rate.

ECO_Mental

https://www.boards.ie/discussion/comment/119941881#Comment_119941881

I am only in my house one year and I have a A2W heat pump as well and I am still learning, and for last winter I didn't have much data but now I am logging my Heat Pump circuit, so I know when it comes on or not.

You are right about the thermal mass though, for the last year I have just used the room stats to call for heat. Every room has a stat and to be honest what I am finding is the heating only really comes on at night anyway when the outside temp drops to really low so I don't really worry about setting for the night tariff it naturally does it anyway.

My house will hold 19-20 deg in most rooms without any heating (A1 BER) But one day last week one of the rooms was at 19deg and one of my young fellas was doing his homework and my missus decided to set the temp to 21.5 degs for the poor little fella... and I didn't know, and the room was set for 21.5 deg for overnight. It was only the next day when I went into the room and realized Jeese this is hot and saw the stat set and set it back to 19.

But what really surprised was that room held 21 degs for 2 days without any heat been called for. I could still feel the floor warm 2-3 days later...this has changed my whole though process on underfloor/heat pump heating. I tried this method for a couple of rooms over the next few days and it also worked. So there is merit in it.

We are having really mild weather the last few weeks/months, so my house has not been calling for heat at all so I have not had repeated this, but we are looking as a bit of a cold spell over the next few days and I might try it again.

BoardsMember

https://www.boards.ie/discussion/comment/119944563#Comment_119944563

Interesting, I'd say you have some people here jealous of the level of insulation/airtightness your house must have. Do you know how deep your slab is, or any other details related to the UFH?

How efficient are heatpumps for DHW? Seems like the case for them is pretty clear in relation to heating to lower temps, but they use more electricity the harder they have to work. If you were converting to UFH/A2W heatpump from gas combi, and the gas boiler was still working efficiently, would it be worth considering running A2W heatpump for UFH and gas combi for hot water? Max efficiency for both demand for hot water?

graememk

https://www.boards.ie/discussion/comment/119949530#Comment_119949530

Say about 3-4ish

https://youtu.be/DO9uccP49_g

That heatpump is doing DHW only.

ECO_Mental

Here is my heat pump consumption since end of Jan this year when I started logging it. This is a moving 7-day average just to smooth out the ups and downs. Heating stopped in March so you can see about between 4-6kWh a day on average during the summer months. Just to let you also I have a 300 liter tank on a 3 bar pump and it NEVER runs out of hot water (despite my kids trying their best to run it dry) and heats on demand it not on a timer or anything. Just let it do its thing.

redmagic68

https://www.boards.ie/discussion/comment/119939215#Comment_119939215

That’s tidy job. You could find a market for those lights too

ConorC1

How does this happen? 🤷🏻

I've DHW set to 42 but yet it's 57

Calahonda52

The last line:

LS: enabled brings it to 60 or so periodically

Nelbert

As above legionella cycle will bring it to 60+ at whatever frequency your installer set....

Mine happens at 2am once a fortnight I think.

Is 42 very low or is my 50 very high? I've mine set to 50 with 10 offset so it heats back up to 50 when it gets to 40.

Solar and an Eddi planned for next summer to boost it to 60-65 regularly with the sun as at that temp we'd have enough for hot showers each morning with no heat pump driven reheat. Only save a small but of night rate but every little helps.

hero25

https://www.boards.ie/discussion/comment/119952304#Comment_119952304

@ECO_Mental very impressive figures! I have a new build, A2. In it a few years. My heating would run for approx 70 hrs in april and maybe a few in May also. Any tips on how you manage to have heating stop in March and no need for heating in April?

Any others got similar experiences?

ConorC1

https://www.boards.ie/discussion/comment/119959226#Comment_119959226

All depends on what matches your needs. 42 is more than hot enough for showering (for us anyway) and washing pots or pans and that

keno-daytrader

https://www.boards.ie/discussion/comment/119959251#Comment_119959251

We have an A2 house, airtightness almost passive. Our heating requirements usually stop in mid March never needed any in April or May. temp set at 21c.

Do you know what your blower door test was for airtightness?

hero25

@keno-daytrader Blower door test result? afraid not! what might that be called on a detailed BER report?

ECO_Mental

https://www.boards.ie/discussion/comment/119959251#Comment_119959251

Airtightness in my house was 2 or a just a bit over, but I think its actually a bit better than that as one sliding door the seals wasn't correct and it had a small draft but that has been fixed and other door.

Regarding heating stopping in March to be honest again, I think that was more to do with it been unseasonably warm in March this year. My house will hold 18-20 deg most of year without any heating. On cold windy nights it will call for it alright but as all the advice if you set your room temps too high you will call for heat. I don't have any room that is set above 20 deg and bedrooms are 19-18 deg. I know if I set a room to 21deg my heating will be on a lot. If I leave it at 19-20, it should not come on that much, apart from the very cold windy nights. If I feel a room is a bit chilly in an evening I will just up the temp to 21 deg and turn it back down to 20 when going to bed. But that will only be in the living room.

I do have a room stats in every room and hallway but again I just leave it alone and if it needs heat it will call for it. The graph below is a graph of some temp sensors I have around the house and as you can see, they are between 18-20. One of the lads has his room set to 18deg so that's why is a bit lower than the rest.

This is only my second winter in the house, so I am still learning how best to manage it but the number one rule as I can see is not to set the room temps to high...

ECO_Mental

Oh I forgot I did actually probably switch off the room stats in the rooms around April. What I found that a door left open because its a nice day or one of the kids would open a window it could drop the temps to call for heat even though its warm enough. Leaving windows open in April May when it could still be cool outside at nighttime will end up in calling for heat when there is no need.

simpsimp

https://www.boards.ie/discussion/comment/119952304#Comment_119952304

That looks a lot like our usage with HP. May I ask what are you using for logging? Our Daikin gives us a visual only, but we can't output numbers.

BoardsMember

https://www.boards.ie/discussion/comment/119960056#Comment_119960056

Not sure you get a blower test on a BER. As far as I know, the BER gives a score based on what is used. Whereas a blower test effectively tests how well measures were executed in relation to airtightness.

In extreme cases of poorly executed work, you could have an A rated house that is expensive to heat because of poor air tightness - poorly installed windows, poorly executed draught proofing membranes etc....none of this shows on a BER.

ECO_Mental

https://www.boards.ie/discussion/comment/119960188#Comment_119960188

Yeah, that was my problem also so I set up Home Assistant Home Assistant (home-assistant.io) on a Raspberry PI4 to log a number of key circuits in the house, Heat Pump, Zappi car charger, Utility room, Solar PV and the main ESB incomer and the kitchen Island with dishwater etc.

I can see when things cut in or out and how much they are consuming, if you want to start managing these things you need to start measuring, As the saying goes. I would recommend Home Assistant it can do lots more than energy.

.

hero25

found below (its been a few years!!). at the time i was advised below 3 was good!

Air Test Result Summary Recorded Permeability at 50 Pa, q50 [m3/h.m2] : 2.952 

and no stat (including the main unit) is higher than 19degrees ;-(

simpsimp

https://www.boards.ie/discussion/comment/119961570#Comment_119961570

Thanks! Looks interesting and also can see instructions for my Synology NAS via Docker which might suit my set up here.

ECO_Mental

https://www.boards.ie/discussion/comment/119962436#Comment_119962436

If you have a NAS and can use docker then you are more than halfway there....easypeasy after that. I use ShellyEMs to log the electrical circuits that I want Shelly EM they are great and HA picks them up straight away. You can use the Shelly3EM as well that is designed for three phase but you can use it for 3 single phase circuits instead.

There is a bit of fiddling about in your main consumer unit to install them that you need to be careful (don't get electrocuted)

I had done a bit of a write up on installing them in another forum see here Power / Electricity Apps? — boards.ie - Now Ye're Talkin'

simpsimp

That's great, thanks for the tip, @ECO_Mental

I have Home Assistant running now on the NAS and will look into the Shelly EM route.

Looking at your notes now in the other forum...

ECO_Mental

https://www.boards.ie/discussion/comment/119962595#Comment_119962595

Well, the Shelly uses CT Clamps to do the actual logging but the Shelly needs power itself so that's why you just you need to wire and live and neutral into a trip to power it. It looks complicated but not really, but if you are not comfortable doing it then it might not be for you. I presume there are battery powered energy monitors, but I never looked into them.