Dave10

Thanks... Made good reading. Basically, I'm reading it as I don't need one. My reasons being:-  Buffer tanks are unlikely to be required when the heat pump can modulate (i.e. if the heat pump is not fixed speed).  Buffer tanks should not be installed in unheated spaces. My HP is not fixed speed. The only place I can install one is in my annexe.... Which is not heated...

Forgot to add in my first post I live in Portugal and tradesmen here have some weird ways, to say the least. We asked about the having the HW tank in the house, but was told it's not possible..... for whatever reason..... Lost in translation. Yes, we do have a hot water circulating system and it does seem to work well. System seems ok. Another heating company suggested the idea while they were fitting PV panels. Was my thought that perhaps I could save on electric because when temps here go below 3 degrees the HP gets very thirsty.

Hi, New to the forum and my knowledge of ASHP's isn't vast, to say the least.... So please go easy on me.. A bit about what has been installed... A new build house fitted with a Riello Nexpolar 15k/W ASHP which is connected to UFH (approx 300 m2 ) and a 300 Litre DHW tank. The UFH has 8 zones, each controlled by its own thermostat. The original design plan was to heat the UFH and DHW with a Biomass boiler, but before it got installed we were given the option of ASHP instead. After a couple of nights reading up on them, we decided to go with it. Our setup probably isn't ideal.... We also had an annexe built and all the gubbins regarding the heating are in it, so the HP and DHW tank etc are about 40 - 50 metres from the house. No buffer tank has been installed, but I have recently been reading about them and spoke to another heating company who highly recommends one for my setup. He quoted me for a 200 Litre tank (size based on 10 - 14 Litres per k/W of the HP) and said the big advantage would be when only 1 or 2 zones in the house are requiring heat. I have since spoken to the engineer who originally planned the heating setup for the house and he said I wouldn't really gain anything..... So to say I'm a bit confused is an understatement. Your thoughts and comments most welcome. Dave