Heat Pumps - post here.

randombar

Hi Folks,

Had my first visit from a heat pump guy yesterday.

Junior guy taking information moreso than anything else I reckon.

250sqm house averaging 1000l of oil per year (Heating and HW)

Recommending Daikin Altherma Monobloc to tie into the existing system.

Waiting to hear back from BER/Energy guy in relation to audit.

Radiators look fine apart from maybe 1.

I can't remember the size of HP he gave but I think it was just a calc based on BER (B1) * sqm, until I get a better reading.

He did say having the back boiler in with the system would be a big no no. What do people here think?

I'm still interested in milling UFH and replacing rads. Does anyone know how much better a HP works with UFH rather than Rads (just trying to justify the cost tbh)

Nelbert

https://www.boards.ie/discussion/comment/120924413#Comment_120924413

UFH can run at much lower temp than most rads unless you go for very large rads.....

Which means the heat pump can run more efficiently as it's not trying to get the water north of 50⁰ to circulate it.

And if done right your floor becomes a giant heat store.

In winter mine heats up the floor slab in the morning during night rate. And then it's rarely needed again during the day for downstairs (bit of heat topping up for the upstairs rad heated bedrooms in the evening on cold days).

So UFH has 2 main benefits.... Being a heat store off night rate electricity and aesthetics of no radiators.

It's also a more controlled heat so the boss had to get used to there being no blast of heat as you come home in winter, just always a comfortable temp.

randombar

https://www.boards.ie/discussion/comment/120926854#Comment_120926854

any idea of the avg efficiency improvements, i.e. save x% of energy, seeing figures of 25% (trying to justify the 8k cost of milling and installing ufh :D)

graememk

As for no back boiler,

Generally heatpumps want a sealed system and a back boiler(uncontrolled heat source) needs a vented system, so it can boil off if something was to fail.

Possibly UFH would work best on a sealed /pressurised system too.

I cannot remember the name of the company but they have equipment to be able to put a back boiler onto a sealed system, they separate each system using a plate heat exchanger and pumps. It's a lot more complicated but is doable.

I have been told that heatpumps will work on a vented system but would be outside a lot of the manufacturers guidelines. (You can have a sealed low pressure system too with 0.5 bar vs the normal 2bar on a sealed system)

the_amazing_raisin

You could get hot water using the back boiler with a dual coil cylinder probably, one for the heat pump and one for the back boiler

You need a dedicated permanently on radiator with the back boiler to ensure it doesn't explode IIRC. So you'll end up with a radiator or two that only get used some of the time

randombar

https://www.boards.ie/discussion/comment/120927082#Comment_120927082

Have solar thermal as well, not sure if it's worth all that hassle to heat water I mightn't ever need.

Nelbert

https://www.boards.ie/discussion/comment/120926887#Comment_120926887

Only properly in to energy monitoring since renovation not before.

Best I can say is despite the massive increase in energy costs my total energy bill is the same as it was before.....

8k for milling the floor alone though..... That could be prohibitive vs large low temp rads....

graememk

https://www.boards.ie/discussion/comment/120927770#Comment_120927770

back boilers really suck heat out of stoves, If you are still sticking with a stove, get a normal one (ideally one with its own air supply from outside) and any small wood fire would put you out of the room.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120928213#Comment_120928213

I've seen stoves from a company called Fondis which are direct air from outside but can also be fitted with secondary air ducts in the room to pipe warmed air around the house. So you warm a bigger space instead of ending up with one room at 900C and the rest of the house freezing

It seems a bit of hassle but I was wondering would it work to pipe the stove air output into the output of an MHRV system via a pipe union with a one way valve to stop the MHRV pushing back against the stove air

randombar

Is there any way of rough calculating the HLI from the avg energy consumption in a house?

e.g. house uses 1000l of oil and is roughly 235msq

sydthebeat

https://www.boards.ie/discussion/comment/120931330#Comment_120931330

Nope

HotSwap

https://www.boards.ie/discussion/comment/120927770#Comment_120927770

What does milling mean? Just ripping out the concrete like?

randombar

https://professionalplumbing.ie/underfloor-heating-retrofits/

HotSwap

https://www.boards.ie/discussion/comment/120931956#Comment_120931956

Ok. Assuming it’s a concrete floor with no insulation this seems like a really bad idea; all the heat will just be sucked into the concrete slab.

And if you did have an insulated floor with no UFH; why not just use one of the low profile systems that only adds 10-12 mm to your floor level.

randombar

Have 150mm of insulation. Was looking at the low profile kits all right but I reckon direct to the floor would be a better thermal mass etc.

HotSwap

https://www.boards.ie/discussion/comment/120932014#Comment_120932014

thats great insulation… the cost would be the deciding factor for me; as long as the heat is going into the house and not into the ground under the floor your winning.

in fact I might prefer to have less thermal mass; I’ve never lived in a house with underfloor heating in screed; but I’ve stayed in a few for several days and they were always too hot for me; and if you turn off the heating to a certain room; it keeps getting heated from the concrete mass.

randombar

Might need some help with all of this. Any technical advisor recommendations in Cork? Can someone PM me?

HotSwap

https://www.boards.ie/discussion/comment/120933748#Comment_120933748

Just look up the list on the SEAI website and phone a few of them. Some of them might give you a bit of informal advice over the phone.

Dave_D_Rave

Lads I have a misubishi ecodan installed.

Just through the settings for the app on my phone and I see that the hot water setpoint can be set from 40 to 60. Currently set at 50.

Are there any dangers of raising to 60 ?everyone I chat with has theirs set at 50.

Why is 50 the set point of choice for so many ?

graememk

https://youtu.be/oJeyc_cGIMU

This is explains it well.

As for side effects, higher will be less efficient, lower is more efficient (takes less electric, but water won't be as hot)

Dave_D_Rave

Great video I suppose I have an excess of solar which I was going to put to heating setpoint of the tank up a bit more.

The inefficiency wouldn't concern me as much as the solar would be picking up the excess in general.

The video actually highlighted another concern which I didn't take into account scolding of vulnerable people from hot water.

I have a few smallies around so might just hold off on raising.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120935764#Comment_120935764

Since you mentioned having plenty of solar power, you might want to look at using the heat pump as a solar diverter. Seems the Ecodan should be able to do this based on the forum thread below

https://forum.buildhub.org.uk/topic/20502-mitsubishi-ecodan-smart-grid-what-does-it-do/

Dave_D_Rave

Thanks for that I have an Eddi installed I just need to setup the heating element to the Eddi I even purchased the additional relay card and PTC probe months ago but never got around to installing it.

Nelbert

https://www.boards.ie/discussion/comment/120936628#Comment_120936628

Eddi aside. My ecodan has the immersion element take over above 55⁰.

It's set to do a legionella cycle every 15 days at 1 or 2am which brings it to 65⁰.

That's based on my install anyway.

Keep those things in mind (although you can edit legionella cycle settings yourself) when setting setpoint.

My longer term plan is to get an Eddi for the immersion but have it's max temp at the 65 of the legionella cycle.

Cyrus

folks sorry this is a long thread but was directed here from the solar thread,

we have an a rated house with a heat pump and UFH, also have an EV so use a day night rate. Are there optimisations i could make with the heat pump to use more night right electricity rather than day?

Its samsung if thats any help.

Mr Q

https://www.boards.ie/discussion/comment/120961106#Comment_120961106

How is it set up now? Do you just set the temp and let it work?

I only heat DHW at night using my HP. Do this first if it is already not set this way, assuming it can meet your DHW needs.

I don't turn up the heat during the night as it doesn't make sense in my setup. A lot of people will heat the house during the night and this will mean much less day units are needed. But still have the house warm during the day.

randombar

Is there a place I can ask about what people think of estimates?

14kw Daikin Monobloc heat pump,

using existing HW cylinder,

weather compensation,

energy metering facility,

web enabled control of heat pump and commissioning included.

Grant processing and inspection attendances also included.

This price includes the electrical and plumbing works involved with a standard heat pump installation. Plumbing works would be very straight forward. Connecting to existing plumbing for old boiler etc.

€18,000

the_amazing_raisin

https://www.boards.ie/discussion/comment/120961106#Comment_120961106

I tried something similar last year, I set the temp downstairs higher at night to try and get the house to build up some heat and reduce the heating load during the day

It sort of worked, my percentage of night rate usage went up, but my overall consumption also went up so bit of a draw

It might work better with UFH than radiators because you can store heat in the concrete floor better

Cyrus

https://www.boards.ie/discussion/comment/120961193#Comment_120961193

at the moment i just had the thermostats set at 20/21 degrees depending and leave them at it!

how do you set the water to heat at night?

ColemanY2K

https://www.boards.ie/discussion/comment/120961520#Comment_120961520

That sounds incredibly expensive.

I paid €12,900 for an 8kW heat pump, cylinder and underfloor heating kit.

The heat pump alone cost €4,400 + VAT. A 14kW would cost a bit more but not a whole pile. The rest on your quote will cost peanuts.