Heat Pump for cooling

samdeluxjones

Has anyone ever used their heat pump for cooling the house via UFH?

If so what are the optimal settings used?

Thanks.

Borzoi

Most manufacturers don't recommend it with UFH because of rrisk of forming condensation on the floor

samdeluxjones

https://boards.ie/discussion/comment/117643076#Comment_117643076

Where is the condensation formed, on the floor surface itself?

keno-daytrader

https://boards.ie/discussion/comment/117646236#Comment_117646236

Keep the flow return higher than the dewpoint and your floors wont condense water vapor. You will get condensation on the manifolds and exposed uf pipes, but not an issue if addressed.

Also a good idea to have a condensate pipe installed from your unit inside the house, if your going to cool the slab with the heat pump. Most have an evaporation tray and that may suffice, depends on the unit and how much condensate the refrigerant pipes produce.

samdeluxjones

https://boards.ie/discussion/comment/117646583#Comment_117646583

There is a drain off the back of the unit.

We have HRV so exposed moisture doesn't last long anywhere in the house.

Did a bit of research and the average temp of the water will be 16-18 degrees. The house is hitting 30 degrees at the minute so If I can get that down to 25 It would make a huge difference..

keno-daytrader

https://boards.ie/discussion/comment/117647053#Comment_117647053

wow 30 is hot, do you have summer bypass on your MHRV? Will make a massive difference at night if you turn up the fans.

starlady1

https://boards.ie/discussion/comment/117647084#Comment_117647084

I have MHRV and air to water heating. I turned on summer bypass the last few evenings and found very little difference.

I wonder would it be expensive to put in air conditioning when MHRV is already fitted. Bedrooms are nearly 26 degrees at night at the moment.

samdeluxjones

https://boards.ie/discussion/comment/117647084#Comment_117647084

The first summer I had the HRV I quickly found out the summer bypass is not worth a fiddlers.

If the outside air is warm and this also gains a few degrees entering a warm house you would need a HRV for every 2 rooms of the house to make any noticeable difference. Max fan with all vents blocked bar kitchen/sit and bedroom might drop a degree..

I Have summer bypass from April-October every year and still have to open windows and doors during the day to try cool the house.

samdeluxjones

https://boards.ie/discussion/comment/117649109#Comment_117649109

I can buy one of these for my ventilation unit but is almost the same price as my whole system cost fully installed and no guarantee it will work effectively. https://www.phstore.co.uk/zehnder-comfocool-q600

starlady1

https://boards.ie/discussion/comment/117650072#Comment_117650072

Thank you that is the same price more or less as my heat recovery system cost to install. I might call the plumber that installed and see if he has any solution.

keno-daytrader

Interesting on the summer bypass comments. During the day we have the mhvr set to a low fan speed, but at night the speed in increased to 80% with the bypass on, have found the house is cooler by 3c in morning when hot weather is here just with the bypass and no cooling from the heatpump.

samdeluxjones

I blocked 5 supply vents in unused rooms(stuffed old t-shirts in the opening) and it has made a significant difference to the rooms we use, dropped from 29 to 27 overnight. The weather did get cooler today so the cool breeze is making a huge difference. My fan speed is 33% 66% and 100% I left them at 66%

I also turned the cooling function on the heat pump and it is definitely cooling the floor most noticeable on tiled surfaces..

bilasy

renovating the house, installing heat pump very soon, can you set it to cool in summer ? If yes how you go that? Plumper / builder reluctant to go cooling claiming it will cause condensation on the tile , proposing AC unit instead , I’m not very keen, help much much appreciated

Wearb

The advice you're getting is correct.

The other option is air to air. That entails installing ducting to all areas and is really only a viable option with a new build.

bilasy

the quote for 2 units AC is 10 K , does that sound reasonable?I’d have thought around 7-8 K only

bilasy

It’s like new build ( demolished and rebuilt)

Wearb

https://www.boards.ie/discussion/comment/121506831#Comment_121506831

I've no idea of prices on that stuff.

I thought you were going with air to water heating and just a single ac unit to cool a single area.

bilasy

https://www.boards.ie/discussion/comment/121506898#Comment_121506898

You’re right,that’s still the plan, just asking before committing to 10 K for 2 AC units

Wearb

https://www.boards.ie/discussion/comment/121507217#Comment_121507217

These AC units can also be used for heating, perhaps allowing for a smaller A/W heat pump. I'm neither recommending or advising against this. Some people don't like the heat blowing from those a/c units.

Sleeper12

https://www.boards.ie/discussion/comment/121506831#Comment_121506831

A mini split air to air is around €4000 for two rooms. A mini split for one room is under €3000.

As far as I know there are no grants for air to air. They can get closer to the same COP as air to water but government doesn't want to encourage AC use so no grant

jasonlane

I've often wondered if it would be feasible to make an extra loop off the manifold and run that to a type of heat exchanger within the MVHR ducting to provide chilled air to the house.