Which Heat Pump recommendation would you pick

mta999

Before you go spending 10 grand or whatever it is you might want to get Octopus back and go over what you plan and find out why they think it won't work - you never know they may be right!

NedS

Whilst a buffer tank can improve efficiency by reducing short cycling, it can also have a negative affect. because it provides hydraulic separation between the heat pump side and the heating system, the HP has to operate at a higher flow/return temperature compared to the CH side. The difference may only be a couple of degrees, but it is likely be enough to go from a top performing system to a meh installation (or worse). Worth discussing the options with your installer. Also read up on the downsides to buffer tanks before trusting anything ChatGPT has to say.

Another reason often given for installing a buffer tank is to ensure the system has sufficient volume to pump round if/when a heating zone is shut off - Wrong solution to the problem in my opinion. A small volumizer tank is a better solution if zoning is baked in to the system design.

Couldn't agree more. A buffer tank is normally used to mask (solve) other issues. It's an easy option for an installer at the cost, in terms of efficiency, of the home owner. The system will work, but running costs will be higher as a result of reduced efficiency from running at higher temps due to heat losses across the buffer.

Any installer who recommends a buffer tank (not a volumiser) on all installs regardless is a huge red flag. In this case there does at least appear to be a genuine reason for considering a buffer tank, and it may likely solve the issue at hand. Given the offending pipework cannot easily be replaced, solving it with an additional pump or radiator is likely a far better solution for the home owner (buffer tanks introduce their own set of problems if flow rates are not evenly matched across each side of the buffer due to hydraulic distortion effects).

swanny65

Whilst a buffer tank can improve efficiency by reducing short cycling, it can also have a negative affect. because it provides hydraulic separation between the heat pump side and the heating system, the HP has to operate at a higher flow/return temperature compared to the CH side. The difference may only be a couple of degrees, but it is likely be enough to go from a top performing system to a meh installation (or worse). Worth discussing the options with your installer. Also read up on the downsides to buffer tanks before trusting anything ChatGPT has to say.

Thanks again. Clear what I need do next and will speak with the installer next week.