Starting out on my heat pump journey

[HML]

Anyway, heatpunk recons we have a heat loss 6916w at -3.2c, so a 7kW Aerotherm Plus should be sufficient. It also says our total annual demand is 16967 kWh a year, which seems at odds with our actual gas usage.

Our annual gas usage for 2023 was 9099 kWh, that was for heating, hot water and our gas hob.
For 2024 up to 19 December was 8587 kWh, gas hob was removed in July

Any thoughts on why heat punk differs so from much on past actual usage???

1 - the last 2 years have been rather warmer than average.
2 - you live in the south east so the heat punk outdoor temperature may be lower than your actual temperatures.
3 - your air change may be a lot better than that assumed by heat punk / MCS. There are discussions on the OEM forum about the MCS air change rates being too high and producing over estimated heat loss figures.

[Ronski]

Yes we've certainly had warmer winters, can't remember the last really cold one.

As for the ACH rates, I had adjusted them all down from what Heatpunk intinitally entered, I've seen mentioned previously that they are way too high. What I've used is shown in column F in the screenshot in my previous post.

[spread-tee]

Hi Ronski, I am starting to think along the same lines, we "only" have six zones for the heating but as we rarely have more than any 2 on at once I am thinking that the pipework will be fine, our largest zone is 3 pretty big rads fed from 22mm primaries and then 15mm secondaries. I would think you may get away without uprating loads of pipework if you have separate timings too.
I will follow your thread with interest.

Desp

[NoraBatty]

One thing to keep in mind, is that heatpumps can also cool the house. Whoever you speak to about install, ask them if they are able to design a system for optimum cooling as well as heating.

Ive not looked into it as dont need it up here, yet... but heatgeeks use theirs to cool their offices, and ours has a cooling option, but i dont know what is needed to maximise this feature, if anything.

[Ronski]

Hi Ronski, I am starting to think along the same lines, we "only" have six zones for the heating but as we rarely have more than any 2 on at once I am thinking that the pipework will be fine, our largest zone is 3 pretty big rads fed from 22mm primaries and then 15mm secondaries. I would think you may get away without uprating loads of pipework if you have separate timings too.
I will follow your thread with interest.

Desp

Having separate zones, unless a very big house is now considered a bad idea. Heat moves from warm to cold, so having cold/unheated rooms mean the heat will move through the walls to the unheated rooms. My daughters room which has been quite cold, it had two unheated rooms either side, once I turned these two rooms on, the temperature in her room improved quite a bit.

https://www.heatgeek.com/why-not-to-zon ... r-boilers/

One thing to keep in mind, is that heatpumps can also cool the house. Whoever you speak to about install, ask them if they are able to design a system for optimum cooling as well as heating.

Ive not looked into it as dont need it up here, yet... but heatgeeks use theirs to cool their offices, and ours has a cooling option, but i dont know what is needed to maximise this feature, if anything.

They are, but it brings other issues, the BUS grant is currently only for heating, although cooling could be turned on later, it also brings issues of condensation on pipework, and radiators are not very good at cooling so you'd ideally need fans coils. I think I've read quite a few threads on here discussing it.

[Ronski]

Looks great, very nice set up.

From my recent install, make sure the heat calc is detailed and takes a couple of hours.

Ensure HP has plenty of open space around it.
Go big on the pipework, remove as many restrictions as you can.
Check all the pipe insulation especially on the bends. Armaflrx will split along the seam under pressure on a 90 deg bend.
Bedroom thermostats are great!
The time and effort you put in now will be a large part of your end result for the next 20 years.
Ask the installers what the minimumn scop they promise.

Looking forward to watching your adventures. Everything good I heard about these systems is true. I've seen nothing negative apart from you cannot have your HW and space heating on at the same time. As the home is acting as one big storage heater you won't notice the heating being off for a wee but while the hw charges. Thought I'd mention it as it was a surprise to us but that was due to old way of thinking.

Going outside isn't as much fun as it used to be.

Thank's, that reminds me, I didn't cover the location that I have in mind for the heat pump, I think there is plenty of open space, and its not going to be near any boundaries either. The garage at the bottom of the picture is about 5.7 meters from the wall. The wall to the left of the heat pump has a window, and around the corner going upwards in the picture is French Doors, I think both should be far enough away not to pose a problem.

[spread-tee]

Hi Ronski, I am starting to think along the same lines, we "only" have six zones for the heating but as we rarely have more than any 2 on at once I am thinking that the pipework will be fine, our largest zone is 3 pretty big rads fed from 22mm primaries and then 15mm secondaries. I would think you may get away without uprating loads of pipework if you have separate timings too.
I will follow your thread with interest.

Desp

Having separate zones, unless a very big house is now considered a bad idea. Heat moves from warm to cold, so having cold/unheated rooms mean the heat will move through the walls to the unheated rooms. My daughters room which has been quite cold, it had two unheated rooms either side, once I turned these two rooms on, the temperature in her room improved quite a bit.

https://www.heatgeek.com/why-not-to-zon ... r-boilers/

One thing to keep in mind, is that heatpumps can also cool the house. Whoever you speak to about install, ask them if they are able to design a system for optimum cooling as well as heating.

Ive not looked into it as dont need it up here, yet... but heatgeeks use theirs to cool their offices, and ours has a cooling option, but i dont know what is needed to maximise this feature, if anything.

They are, but it brings other issues, the BUS grant is currently only for heating, although cooling could be turned on later, it also brings issues of condensation on pipework, and radiators are not very good at cooling so you'd ideally need fans coils. I think I've read quite a few threads on here discussing it.

Hmm I need to try and get my head round that, I'm sitting here in the loft at 18.5 degrees quite comfortable with just the underfloor heating on the ground floor and the three bathroom rads on. Sure some of the house is warmer than other bits, we're all happy with that, but how do I use less energy by turning on more rads with a boiler? I am already down to about 40 degrees flow temp would the cop rise enough to compensate if I had a HP??

Heat geeks definitely know their way around a heatpump system but something sounds flawed to me

Desp

[Ronski]

It seems to make sense to me, we were heating the daughters room, but it struggled to stay warm and lost heat quickly. The dividing wall is 60mm thick, that wall was leaking heat to the unheated room, which in turn loses heat, although probably not so quickly as the delta is smaller. Turning the heating on it that room certainly seemed to help, whether it now cost more to run, I'm not entirely sure.

I also think the idea is to get the whole area within the insulated envelope up to temperature, so it maintains it more easily.

[Joeboy]

On a 3deg outdoor day we consistently see a cop.of 4.4. That's combined space&water heating. Space heating alone would be closer to or over 5.

We have 13 degs coming for the next couple of days. I don't want to say what the cop will rise to but last time the air was that warm we did see figures starting with a 7.for space heating.

We also have a lagging wall due to poor insulation. With the rest of the house at a consistent temperature the lagging rooms show a lot more (2 of). I've not touched it yet but as soon as New Year is past I'm going for it.

HP site looks open so it will be pulling fresh ambient air when you install.

On our old electric heating system which was essentially 1:1 we averaged 80kWh's per day consumption at this time of year. Roughly speaking that has halved. I say roughly as the outdoor temperatures have a direct and massive impact on the indoor consumption goings on. We have seen days when we dipped into the 30's of kWh's per day. Mind blowing to see that.

I took this screen grab moments ago. 2 degs outdoors.


I assume the heatcalcs shown are from a guesstimate online? I ask as when our calc was complete the figures on loss/use were close to what we've seen in reality historically. We came out at 7.9kW heat loss and a 7kW pump went in.

Cop is weird as it squirrels about constantly as the HP adapts to outdoor reality and indoor demand and it's on a short window of a day. I'm too early in ownership to have built a meaningful scop. Although I do like the right hand column.


Our hwt which is 200ltrs has been great. I've not actually looked to see what kW is going into the hwt during hot water cycle from the HP but it seems to be quite fast. I upped the cylinder temperature to 55 degs as swmbo said it wasn't hot enough for dishes that don't make it to dishwasher.

Daughterly arrives this evening and the real test begins.

[Ronski]

Be interesting to see how you get on with your daughter home with regards to hot water, presume that will be three of you in the house?

Heat Calcs are done on a specialist site inputting construction details etc. Others I've seen has said its pretty accurate, but obviously depends on the data used.

https://heatpunk.co.uk/

Daughters bedroom lagging quite a lot overnight, I really need to get that window sorted, and rule that out, plus add some more loft insulation, perhaps a job for next weekend.