ASHP linked to log burner boiler

[Lewis88]

11 minutes ago, ProDave said:

Pretty much like us.  The ASHP does most of the heating and keeps the house at 20 degrees, but it is nice when it is grey and wet outside to indulge and get the living rooms up to 24 degrees at no cost with the WBS, something we would not want to pay to do by just turning up the thermostats.

 

And of course it then takes a while to cool down before the thermostats click on again and the ASHP comes on so it saves electricity.

 

But it is worth striving to get close to passive house standards, particularly the air tightness and an MVHR ventilation system.  That is a revalation to live in.

Absolutely, I intend on making it as air tight as I can and using quite a bit of insulation. I have a feeling that as suggested, a standalone externally fed stove will be the best solution for me. Unless I can get a small boiler stove to feed an unvented cylinder used by the ASHP. For the sake of simplicity I think that the standalone stove probably be better suited. Probably a far better idea to invest in solar PV on the rear of the house instead.

[ProDave]

21 minutes ago, Lewis88 said:

Probably a far better idea to invest in solar PV on the rear of the house instead

Solar PV is definitely worthwhile and divert any excess to the imersion heater.

[saveasteading]

On 28/01/2022 at 12:02, ProDave said:

Only fit a room sealed stove, that draws it's combustion air from the outside directly via a duct

Does that not draw air through it (vent to flue) constantly, chilling the fire when it is off, so a cold steel box  in the room ?

[JohnMo]

9 hours ago, saveasteading said:

Does that not draw air through it (vent to flue) constantly, chilling the fire when it is off, so a cold steel box  in the room ?

Our fire has a throttle valve (not sure it's call that) which shuts the air of completely.

[ProDave]

9 hours ago, saveasteading said:

Does that not draw air through it (vent to flue) constantly, chilling the fire when it is off, so a cold steel box  in the room ?

It must do to some extent.  I have just gone and measured and the unlit stove is showing as 1.5 degrees colder than the kitchen cabinet it is sat next to, so it must be drawing a small amount of heat out of the room. But it seems to make no practical measurable difference, that room heats up and retains it's heat as well as other rooms.

[andyj007]

Ii Have this exact set up in our home,

Our  ashp can run as normal, if anyone lights the log burner , as soon as a closed  flow and return temperature loop through the  back boiler reach 45degrees it shuts off the heat pump and circulates this  stove heated water through the buffer tank for under floor..  .  if i boost my HW timer or if the  timer  calls for the hw tank to be heated whilst stove is heating  , it just diverts from buffer tank to hw cylinder...   ..  I have manully turned by ASHP off as i have no need for it,,  the house doesnt really cool down enough between lighting the log burner in the evening..  basically since december when we fired everything up (its a new house) , I tested the ASHP for a couple of days then shut it down .  just lighting the back boiler stove in the evenings along with another stove in our family kitchen diner room.  works a treat.. we do benifit from solar gain when sunny, house is designed to maximise this in summer ..  and i would recommend to any one to take advantage of that.. 

our house is 4000 sq ft. in the bathrooms we have under floor  but i see no need to use energy on those rooms that get used the least, so these are heated on demand with 1000w IR bar heaters..  works perfectly..

When have needed hw and couldnt be bothered to light the back boiler, we just turned on teh heat pump for that purpose..  

next week i will b einstalliung 7.2kw solar array and batteries , with immersion dump.  we will need to figure out the best way (efficent) to heat the water in a month or two when lighting the back boiler will create to much warmth in the house.. 

FYI  house is brick / block with timber clad external , aluminum windows, and heat recovery, full U/f heating, x 1 ASHP to water and (x 2 A2A air con/ heat units not used yet) 

Hope that helps you.

R

Andy