Heat Pumps - post here.

Sounds like UFH may be a cheaper option to run in long term?? Our preferred build has rads but a few others we had looked at but couldn’t secure had UFH on ground floor and I was wondering is that a higher spec thing.

Coming from what we have now, this is going over our heads. But I love the idea of a constant temp maintained throughout the day in winter compared to turning on the boilder and off. And it being plainly cheaper than if we had to run the heating all the time with the gas boilers.

With rads, they basically heat the air thru convention (hot air at the roof dropping to met cold air on the ground, so the air ‘cycles’ around the room itself). Air heats quickly but loses heat quickly. It lacks density to hold the heat. So room temp goes up and down as rads go on and off.

But if you heat a huge slab of concrete (which takes a long time of course), it then radiates that heat into the room. The concrete = thermal mass (that’s something very dense that can hold heat for a long time). And the room can stay are a more constant + comfortable temp. And that heat then also move into the walls (if they are solid) so also helps increase the wall temp – which adds more of a thermal mass to the space.

We're all come across the idea of thermal mass when standing on cold tiles in bare feet. The cold ‘radiates’ out from the floor into your feet. Gives me brain freeze :) Same idea, but the opposite temp. 

It may or may not be cheaper depending on many factors. You can have UFH with a gas boiler also.

Hi all

1. I set the base temperature in my house using the Joule sensor at 20 degrees and, using the temperature control system on the sensor, as I understand it, the sensor will kick in when the room temperature falls to 19 degrees and will keep the heat pump running until the sensor reaches a temperature of 21 degrees, at which stage the heat pump will be switched off until the temperature in the room falls back to 19 degrees.
2. The next day, I set the base temperature in my house using the Joule sensor at 26 degrees and, using the temperature control system on the sensor, as I understand it, the sensor will kick in when the room temperature falls to 25 degrees and will keep the heat pump running until the sensor reaches a temperature of 27 degrees, at which stage the heat pump will be switched off until the temperature in the room falls back to 25 degrees.

My question is, apart from the extra units used in getting the room temperature to the higher temperature initially, would be heat pump use the same number of units maintaining the temperature in both scenarios above?

You'd only need blending valves if your flow temp is too high. Gas can be(and should be for condensing) ran at lower temps anyway.

You might save a few bob on clothes though, ie. you'd be casting them all off at those temps!

This is exactly what I was thinking about so thanks for response.

Most people seems to have UFH in their new builds. Probably a higher spec so didn’t know how someone with rads found it.

Our outdoor unit (Daikin Altherma 3) is at the end of our garden, albeit behind a fence, but it makes almost no noise, even when you're up close to it.

Probably not much good to you, but just for contrast... Hopefully they will be able to help quieten it down.

I have a Nibe similar to yours but with a smaller outdoor unit. I put a small consumer unit on my HP, pump and controls to know how much energy the heating system is using. There is no way of measuring the kWh used on the Nibe unit as far as I know of.

Charging 25 euro yearly for a premium version of an app is taking the piss in my view on such an expensive unit.

Hi again folks,

Anyone got any feedback on Ground Source heatpumps?

Again for my new build, i'm considering going a2w or groundsource.

I have half an acre, with a large front garden - would have about 400M2 to spare there that could be used for a horizontal system.

Thinking if I can dig this myself id bring down the cost of the system closer to the going rate for the a2w so it appears to be a viable option.

Thoughts?

I did ground source with a vertical borehole, and am very happy with it. I did it mainly for aesthetic reasons - didn't want an A2W unit in front of the house. While it is somewhat more efficient than A2W, you won't recover the additional cost back on the efficiency improvement alone. However, I firmly believe that the extra lifetime that can be achieved by having the heat-pump indoors will eventually pay back....if you live long enough and stay in the same house. I live near the sea, and I suspect that A2W units outdoors are unlikely to last more than 10-15 years in Irish weather. I have just thrown out 2 gas boilers that were 23 years old, and could probably have been kept going with a few spare parts which are still available. I would expect an indoor GSHP to last 20-30 years, even if it needs a new compressor or the odd spare part. There are some other advantages, like the near-silent operation of the GSHP vs the noisy fan on A2W. There is also the asset value of the collector, which may add to the value of your property if you have to sell it. The collector will probably have a lifetime of 100 years, so should remain an asset well into the future (if future generations have'nt figured out a better way of heating houses!).

It is important to size your ground source collector. Your heat-pump supplier should be able to do this for you. 400sq m might be at the low end of the area required for a horizontal collector, but might work if the house is not too big, and very well insulated.

Thanks a million!

There are all sorts of collectors on the go at the moment usually when you go online you see the big one that goes around a perimeter of an area, now there seems to be something that looks like underfloor heating pipes - Ill contact a few companies and see what we can do.

With a GS heatpump there is no equipment outside right? Aside from the collector pipes that would then run into the plant room?

Anyone know how to register an Ecodan HP for warranty purposes?

I've tried emailing the only email address I could find for Mitsubishi Ireland HPs and also tried contacting them through Facebook but no reply to either.

Looking at this i don't know what's going wrong with my heating. I used 2300kwh for nov/dec. In January i have been using 33kwh a day. 242sqm new house. 80% of my kwh are the heat pump as it has separate meter i can monitor. House now fully insulated. Attic only finished second week in jan and in the sitting room that was freezing at 14deg, now have 19 most days without heat pump so thats good at least .Getting air tightness test done soon to see if i have draughts i dont know about.

I seriously hope that was it but most of the attic was done for the cold months just not over sitting room and along eaves on 1 side.