umiq88 Posted March 14 Share Posted March 14 New build bungalow 200sqm all UFH. 150mm PIR in floor with 75mm screed, 110mm PIR in cavity with 50mm insulated plasterboard on internal block wall. Originally plan was oil boiler but after pricing everything ASHP is starting to make sense with 7-8year pay back. Also much simpler. Looking for some help with design. This will be self install hence all the questions. Grant Aerona3 (Chofu) 10kW (subject to heat loss calc) Inverter driven and variable flowrate/output temp etc. Grant 300l UVC 2.35m2 area coil. Open to recommendations as the coil seems small. Couple of questions - Do you still need red expansion vessel on low temp system? - On oil boilers is standard to install likes of Spira vent and trap. Is this needed? - What is the best way to plumb UVC coil? Presume a 3 port mixer but how is this typically controlled. - There will be no zoning on UFH just weather comp on ASHP. However main areas are recommended at 20 and bedrooms at 18. How is this achieved? Balancing?? - 16mm pex-al-pex in floor with 150mm spacing. Presume spacing is not that important but 150mm is standard. - 32mm pex-al-pex between ASHP and manifolds. Use water and frost valves. - No buffer/volumizer etc. What do people do for control. I'm based on Ireland so the likes of homely isn't available. Do people just set a weather curve and keep adjusting until optimal or is there a better way to approach. Heatpump has modbus. Link to comment Share on other sites More sharing options...
Post and beam Posted March 14 Share Posted March 14 10kW sounds like a lot for a new build highly insulated single storey Link to comment Share on other sites More sharing options...
Russell griffiths Posted March 14 Share Posted March 14 4 minutes ago, Post and beam said: 10kW sounds like a lot for a new build highly insulated single storey Agree with this, what sort of airtight score are you after. and have you done a heat loss calculator I’ve got 180m bungalow, but with vaulted ceilings up to 5m and my Heatloss calculator was pointing to a 7kw unit. Link to comment Share on other sites More sharing options...
umiq88 Posted March 14 Author Share Posted March 14 Just an estimate when I got pricing. Haven't done calc yet. Anyone have any recommendations for easy to use calculator? Not sure on air tightness either. Will be going highest practical. Link to comment Share on other sites More sharing options...
JohnMo Posted March 14 Share Posted March 14 29 minutes ago, umiq88 said: UVC 2.35m2 area coil Get one with 3m2 30 minutes ago, umiq88 said: Do you still need red expansion vessel on low temp system? Yes 30 minutes ago, umiq88 said: On oil boilers is standard to install likes of Spira vent and trap. Is this needed? Not needed 30 minutes ago, umiq88 said: What is the best way to plumb UVC coil? Presume a 3 port mixer but how is this typically controlled 2x 2 port one normal open one normally closed or 3 port diverter - not mid point 31 minutes ago, umiq88 said: There will be no zoning on UFH just weather comp on ASHP. However main areas are recommended at 20 and bedrooms at 18. How is this achieved? Balancing?? - 16mm pex-al-pex in floor with 150mm spacing Two ways balancing or amount of pipe in the floor, or a combination 33 minutes ago, umiq88 said: What do people do for control. I use a Computherm Q20RF at 0.1 hysterisis and charge floor at a set temperature, not WC, once 0.5 degrees below target it switches the heat pump off. Run on E7 tariff. 35 minutes ago, umiq88 said: Grant Aerona3 (Chofu) 10kW Download the Chofu manual and install as per their instructions not Grants, use their controller to control temperature - no need for any external controls. Link to comment Share on other sites More sharing options...
nod Posted March 14 Share Posted March 14 We’ve just ours commissioned 11.5 Kw 330 m2 over two floors Three vaulted ceilings 5k in total to pay after the grant for the heat pump and all the tanks etc Dont think it will ever pay for itself Im hoping it will be simalar or slightly more to run than a gas boiler Link to comment Share on other sites More sharing options...
SteamyTea Posted March 14 Share Posted March 14 42 minutes ago, nod said: 11.5 Kw What power? Link to comment Share on other sites More sharing options...
JohnMo Posted March 14 Share Posted March 14 53 minutes ago, nod said: simalar or slightly more to run than a gas boiler I am currently running about 30% cheaper on ASHP, compared to gas boiler. When comparing all electric usage, to gas and electric. Battery and E7 helps, but neither would help with a gas boiler. 1 Link to comment Share on other sites More sharing options...
nod Posted March 14 Share Posted March 14 1 hour ago, JohnMo said: I am currently running about 30% cheaper on ASHP, compared to gas boiler. When comparing all electric usage, to gas and electric. Battery and E7 helps, but neither would help with a gas boiler. 1 hour ago, SteamyTea said: What power? 11.5 Link to comment Share on other sites More sharing options...
nod Posted March 14 Share Posted March 14 1 hour ago, JohnMo said: I am currently running about 30% cheaper on ASHP, compared to gas boiler. When comparing all electric usage, to gas and electric. Battery and E7 helps, but neither would help with a gas boiler. That would be a bonus we hate solar panels and couldn’t justify the outlay On this or our previous build Link to comment Share on other sites More sharing options...
Dave Jones Posted March 16 Share Posted March 16 cart before the horse. do heatloss calc to see what you need, correctly sizing is very important for efficiency. https://www.changeplan.co.uk/heat_loss_calculator.php If your build hasnt commenced: Done zone anything. 100mm ufh pipe centres for low flow. marmox blocks first course to delink slab from walls. 150mm cav with dritherm 37 (brickie will thank you) simple mvhr unit to avoid punching holes for erxtractors all over. do that and it will be cheap to run. 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now