Nially

Thanks for your input and taking the time to put that together. It certainly make all the options a lot clearer. I was quoted for a 12kw Daikin mono block unit but I have asked for a requote for a smaller pump. They used standardised parameters to size the heat pump as the house was built in 2014 and I have no accurate heat loss data. Although a near 10 year old house it’s was built and insulated a lot better than the parameters they have used. I should have the new quote back on Monday. I also got a quote of 13,500 for 2 bore holes each 130 meters deep🙈. The payback certainly isn’t there to justify that. I am also meeting another driller during the week to get another quote so I’ll see how that goes. thanks again

Thanks for your input. It certainly was an efficient system and never gave trouble in 9 years. We had all our heating and hot water for 3000kwh per year which is very satisfying for a large house. Repair isn’t a solution/option here so it’ll be a replace ground loop or drill bore holed if I continue with the GSHP

Yes I have the pipe, going the legal road is something to consider but I don’t know would the stress be worth it

Yes thanks I am also thinking of a mono block unit and to mount it 9ft up on the outside wall as I can run pipes across the ceiling to my heating cupboard. I will need new dhw cylinder as you rightly suggested. If a 7kw unit will do the job it will look a lot neater on the wall outside

There are 2 adults and 3 kids. I have no data from the designer as the construction started in late 2013 when passive houses were not that common. I had the house designed by an architect and researched all the construction details myself to get it to passive standard. An engineer then completed drawings based on the spec i provided so PHPP was never used. I competed all the airtighness myself and a lot of the trickier details like closing the 10" wide cavities etc..

Hi There, Yes it looks like very similar performance for both houses. Any reason you didn't go for a heat pump? Based on them figures can a new pump be sized accordingly?

I am thinking the 12kw unit was oversized but at a loss how to calculate if it was. Can anyone help with that? The 290 sq mt house used 3000KWH every year to run the geothermal pump for hot water and space heating, Id imagine them figures could be used to size the heat pump?

Thanks, The combi is in the heatpump so the heat pump does the dhw and ufh. I am thinking the 12kw unit was oversized but at a loss how to calculate if it was. Can anyone help with that? The 290 sq mt house used 3000KWH every year to run the geothermal pump for hot water and space heating, Id imagine them figures could be used to size the heat pump?

Just an update for everyone. So the consensus seems to be Air to water or repair what I have. I wanted to see if there were any other options as I have not explored this area since I built my home in 2015. I am based in Ireland and have been getting quotes of around 12,000 euro for an air to water system which seems ridiculous to me as all the pipework is in place and the unit costs about 6,000. I have had one quote for some boreholes for 13,000 euro. I plan to get a few more quotes before i decide what to do. Thanks for the help.

YES correct, this is they way it should be looped, so please note everyone. The outside of the pipe has stress from being in a bent state over 8 years and eventually will crack. So the larger the radius the less chance of failure.

It is a 12kw Mastertherm Aquamaster inverter combi heat pump. Option to mend is not an option for me as i believe it has failed in several places where the pipe bends at the end of trenches and will continue to do so. We have at least 2 more leaks after repairing one as explained above. I have a patio outside my back door which I could consider lifting to route pipes and move the unit away form the house. Thanks for the suggestion

correct, just the ground loop has failed

The heat pump unit its self is perfect Jilly, just the loop has failed

Hi Alan, Yes my fear is the pipe will eventually fail at every tight turn. We repaired one leak but have at least 2 more (two ground loops so they can be isolated and tested and no pressure in either which means 2 more leaks). I suspect pressurising the loop to 3 bar to find the leaks normally ran at .5 bar exposed the pipes weakness and has split in several places. It s just not worth ripping up lawns and patios and most likely have problems again. Yes it is an MDPE gethermal pipe with an MJS logo on it. Any idea who MJS are? I googled the manufacturer but nothing turns up.

Thanks for the suggestion, yes I had read up on them units and it would be an option for the DHW. I have the buffer tank and GSHP unit near the back. Heating the buffer tank then for the UFH would need a solution

Hi and thanks, Yes correct on your COP and figures I am limited where I can place it so near the back door it will have to be if I go for it

Hi all. I built my home back in 2015 and thankfully I was interested enough at the time to go the passive route. Although not certified It has preformed very well. I have been reading numerous posts over the past few days with great interest. Performance wise over 8 years the GSHP has used 24,000 kwh for space heating (wet UFH) and daily hot water so about 3,000kwh per year. The temperature in the house was set at a constant 22 degrees, upstairs never called for heat as the heat rises from downstairs. I do have an open loop to bathrooms so once any room calls for heat the bathrooms will heat. The house is 290sq mt, 250mm pumped wide cavity with block on flat on interior walls, 0.37 ach air tightness, 400mm of pumped cellulose in the vaulted ceilings and 400mm of rockwoll in the flat ceiling to attic space. So I am now on here as i need a bit of help/advice as our ground loop to run our Geothermal pump has failed. The 32mm pipe has developed stress cracks where is was looped at the end of a trench (1000mm wide trench). We found and dug up one leak and I believe our installer looped the pipe too tightly and over time it has simply developed a crack on the apex of the curve. The leak we found was exactly on the apex of the curve. We had discussions and he is not willing to take responsibility. Digging up my mature 8 year old lawn and garden is now not an option. So I am probably left chasing him through the legal route if I am willing to take on that stress. Luckily enough I have a stove so that is keeping the house somewhat warm. I am now left looking for an alternative heating source. Air to water is the obvious answer but maybe now that I have 8 years of data that might be overkill for my house? I am also turned off by the unit which will have to be retro fitted right outside my back door which is not ideal. Maybe someone might have suggestions how to heat my existing buffer tank? 30 degrees in my buffer would easily heat the house. I would of course also need an option for my daily hot water. Any advice or opinions are appreciated, thanks.