scottishjohn

sips floors used often in russia where permo frost is prevalent -- house is built on plies and then all sips construction floors walls and roof you will find plenty of examples on u-tube of DIY houses constructed this way using both OSB panels and MGO ones

possibly a bit harsh --but would you think a flat with badly specified UFH should command a better price than a STD system that works -- we all seen the slagging ASHP get when badly specfied or fitted in an old house with many basic problems but it was statement that UFH will make it command a higher price - even though he has been told it won,t work I know what my view would be if I bought it and was expecting a good performing system and economical running costs and not something a buyer could check on at all at time of purchase ,only when the gas bills came in would he find the truth of how bad a system I know in England now some house sales have a clause that if things like heating,cooker etc fail or do not work correctly --then there can be a claim back to sort the problem under the terms of the sale agreement -- for a period after sale

no one here is telling you UFH is a good solution and all are telling you it will not work well if you cannot get more insulation under it - but as you seem to know it all I cannot understand why you bother to ask our gurus ? If you can afford 40mm of height -then use part of that to insulate the concrete floor -then add floor covering and fit std rads with plumbing hidden in skirting boards and as you say the floor above is concrete - then to do the right job that should also be using thick insulated PB on the ceiling or you will be heating both the flat above and the one below I would consider your idea to fit that UFH to extract a better price is almost fraudulent as it will not give any of the advantages that UFH does when fitted correctly and will cost more to run that std rads so don,t be telling us you care about the buyer -- you don,t -- its all about the profit to you

will be a failure with NO insulation below -do not fit with on insulation layer ones with no insulation assuming you are using an insulation layer then fitting panels OR you have a full concrete floor with insulation uderneath the slab and then creed on top of your panels and pipes

sleeper wall sounds quicker and simpler imagine making all those holes then finding out they not quite right spacing and then if holes big enough having to cement them all in 30 mins a hole ? x 45 =22.5 hrs !!!-- could be more like an hour each one pretty sure you will build a sleeper wall quicker or attach blocks with rawl bolts to exsisting wall to support each one --would give much more tolerance to jiggle sideways to make them a tight fit on in fill bocks maybe there are purpose made brackets for doing this?

Izodom -- was that from Econekt- the uk agent or direct from a supplier in poland?

the wood will still breathe cos you only do it between the rafters and not on tops of batons

may not be cheapest way -- but If i were wanting to insulate that tiled roof and make it vapour proof I would buy a froth pak - kit and just spray i with closed cell foam --not only will it insulate and make a water proof seal - it will stick and loose tiles in place for ever

and you will still be alive not fallen off the ladder and head like split melon when you hit the floor

If you are going to put up with going up and down ladder with every bit of insulation and trying to string a vpc on your own --then i don,t see building the tower on your own is a big thing the time taken to do this will cut the job time by 50% or more

to work off -- NO not me -other than changing a light bulb

I,m sure there are places if there is no permofrost when nice soggy ground will work well with slinky as heat transfer is 50%better through wet ground than dry . and a holiday home will not be used 24/7 all year round ,so I can see the extra cost of a borehole could be prohibitive but that does not mean that would not be the best solution long term if you have months of -20c temps

I am totally sure that GSHP is a better solution for colder climates but not that convinced on "slinky" type set up for cold climes bore hole yes the extra work to bury slinky deep enough to work in very cold climate with long winter -- could outweigh cost of bore hole I will leave @SteamyTea to explain why you are wrong about parasitic power losses etc --like power to run the compressor etc-

If we got -15c to -23c regularly every year in uk for long periods --then thats when GSP would be a better choice-

power consumption to run the unit against actual heat recovery from the cold air everything takes power to run and COP is measure of kw power IN to KW heat OUT

I bet it don,t say its COP ratio of 3 at that temp will be cop of 1 or less if it can work that low outside temp maybe got an immersion heater in line to lift temp of output if heat pump cannot keep up

No check with makers

if he steps it down at house end ,then normal pump will run it -as the flow rate will be what the smaller pipe can flow --I think you will have more heat loss in the buried though due it holding more volume could be a good idea to put smaller size one up the big one if you feel it is a problem

yes it just moves more air to get the bigger output I have a mitsubishi one a t8kw the 14kw has an outside box alot bigger and 2 fan units instead of one-it just extracts heat from a larger volume of air do you have 3 phase? it would be cheaper running on that i think

I trust this is what you have fitted for the piping https://www.underfloorstore.co.uk/product/uponor-ecoflex-thermo-twin-pre-insulated-pipe and buried it very deep

and for sure it needs to very well insulated like this https://www.uponor.co.uk/products/heat-and-water-distribution/preinsulated-pipe-for-heat-networks over £100 per metre for right stuff

I would have suggested a "catnic lintel this company can do the length you require as they specialise in odd balls 7m is a big opening http://www.harvey-steel-lintels.co.uk/

so why not SIPS for the extension? another choice for you

plenty of drafts - same temp inside as out- so no condensation

a heater will only work when its on - stopping the cold surface from getting condensation ,by insulating it is a better idea +cheaper--unless your going to run the heater 24/7 in winter why do think you car does not get wet oninside of roof ? cos of the headlining