Heat pump quote

FreeBear

stripling said:

@BuildTheWall
"This is my worry. Ordering an electric hob and the installer finds something missing and that requires further spending."

Do you have an electric oven? Is there a fuse labelled in the fuse box? Is your cooking 'built-in' or free standing? If the latter, you can see by pulling out the cooker and looking behind for a wired-in box.

A big red switch on the wall labeled "cooker" would saving having to pull appliances out to look for junction boxes.

If you pulled my builtin oven out, you'd find it plugged in to a 13A socket.

BuildTheWall

stripling said:

BuildTheWall said:

stripling said:

@BuildTheWall
but I assume they have estimated based on worst case basis and also that heat pump works continously? 
While it looks increasingly a poor return financially, the comfort and convenience of having constant warm temperature is making it attractive as I can avoid partner getting annoyed for not turning on heating often.

Also, Octopus estimate on a 50° design temp but if you can over size your radiators you run it on a much lower design temp which is more efficient and cheaper. Mine runs well on a 40° design temp even when several degrees below freezing outside.  I have a 6kw Daikin but I pushed the radiators well over spec (do you have the radiator schedule from Octopus yet?) I'm not convinced by your thinking it's a 'poor return' because if you go the whole enchilada with solar etc., you will be very well set up and 'future-proofed'. 

Interesting. They didnt give me an option to oversize probably thought it'll get expensive and will put me off. 
This is the schedule I received. 

stripling said:

 What size heat pump have 🐙 suggested for you? 

Its Daikin 6kW and 180L cylinder.

Same as me.  Great bit of kit. 
Your radiator schedule looks a bit odd. What's happening in the living room? The two suggested don't add up to the heat loss. 

What are you going to do in the bathroom? 

They agreed to change the towel rail to radiators for £200 in both bathroom and en-suite. Wondering if that’s worth it. 

They refused any further radiator upsizing changes. 

Reed_Richards

stripling said:

BuildTheWall said:

stripling said:

@BuildTheWall
but I assume they have estimated based on worst case basis and also that heat pump works continously? 
While it looks increasingly a poor return financially, the comfort and convenience of having constant warm temperature is making it attractive as I can avoid partner getting annoyed for not turning on heating often.

Also, Octopus estimate on a 50° design temp but if you can over size your radiators you run it on a much lower design temp which is more efficient and cheaper. Mine runs well on a 40° design temp even when several degrees below freezing outside.  I have a 6kw Daikin but I pushed the radiators well over spec (do you have the radiator schedule from Octopus yet?) I'm not convinced by your thinking it's a 'poor return' because if you go the whole enchilada with solar etc., you will be very well set up and 'future-proofed'. 

Interesting. They didnt give me an option to oversize probably thought it'll get expensive and will put me off. 
This is the schedule I received. 

stripling said:

 What size heat pump have 🐙 suggested for you? 

Its Daikin 6kW and 180L cylinder.

Same as me.  Great bit of kit. 
Your radiator schedule looks a bit odd. What's happening in the living room? The two suggested don't add up to the heat loss. 

What are you going to do in the bathroom? 

Coming back to the living room question, it looks as if the two radiators together only cover 78% (39% + 39%) of the room heat loss.  The last thing you want is a cold living room so you need to get this rectified.    

thevilla

BuildTheWall said:

stripling said:

BuildTheWall said:

stripling said:

@BuildTheWall
but I assume they have estimated based on worst case basis and also that heat pump works continously? 
While it looks increasingly a poor return financially, the comfort and convenience of having constant warm temperature is making it attractive as I can avoid partner getting annoyed for not turning on heating often.

Also, Octopus estimate on a 50° design temp but if you can over size your radiators you run it on a much lower design temp which is more efficient and cheaper. Mine runs well on a 40° design temp even when several degrees below freezing outside.  I have a 6kw Daikin but I pushed the radiators well over spec (do you have the radiator schedule from Octopus yet?) I'm not convinced by your thinking it's a 'poor return' because if you go the whole enchilada with solar etc., you will be very well set up and 'future-proofed'. 

Interesting. They didnt give me an option to oversize probably thought it'll get expensive and will put me off. 
This is the schedule I received. 

stripling said:

 What size heat pump have 🐙 suggested for you? 

Its Daikin 6kW and 180L cylinder.

Same as me.  Great bit of kit. 
Your radiator schedule looks a bit odd. What's happening in the living room? The two suggested don't add up to the heat loss. 

What are you going to do in the bathroom? 

They agreed to change the towel rail to radiators for £200 in both bathroom and en-suite. Wondering if that’s worth it. 

They refused any further radiator upsizing changes. 

I'd recommend dualing the towel rail replacements. i.e. have them on the heating circuit for winter but with the option to use electricity in summer.  You don't want the heating on just to dry towels.  It's very easy and cheap to do.

stripling

@BuildTheWall
They agreed to change the towel rail to radiators for £200 in both bathroom and en-suite. Wondering if that’s worth it. 
They refused any further radiator upsizing changes. 

I had a nice trendy towel rail that wasn't going to give sufficient heat in the bathroom at low flow temps and I didn't want to remove it so I found a really nice, small but powerful aluminium radiator  and paid to have it put in myself.  It was definitely a good move! It looks great and packs out the heat. (I hate cold bathrooms).

If you decide to add any radiators your self (or upsize) use a delta T convertor 
You need to take the radiator output at Delta T 50watts (your design temperature) and convert it to Delta T 20watts (which will give you an approximate 40watts design temp).  You can see the final output @ 50 on your radiator schedule. That's how I calculated mine and how I chose the right radiator for my bathroom.

If you wanted to upsize has 🐙 given you the option if you pay? I know they can get radiators far far cheaper than anyone else - as long as they are the same width as what they replace so they slot in - the fitting shouldn't cost at all. 

BuildTheWall

Reed_Richards said:

stripling said:

BuildTheWall said:

stripling said:

@BuildTheWall
but I assume they have estimated based on worst case basis and also that heat pump works continously? 
While it looks increasingly a poor return financially, the comfort and convenience of having constant warm temperature is making it attractive as I can avoid partner getting annoyed for not turning on heating often.

Also, Octopus estimate on a 50° design temp but if you can over size your radiators you run it on a much lower design temp which is more efficient and cheaper. Mine runs well on a 40° design temp even when several degrees below freezing outside.  I have a 6kw Daikin but I pushed the radiators well over spec (do you have the radiator schedule from Octopus yet?) I'm not convinced by your thinking it's a 'poor return' because if you go the whole enchilada with solar etc., you will be very well set up and 'future-proofed'. 

Interesting. They didnt give me an option to oversize probably thought it'll get expensive and will put me off. 
This is the schedule I received. 

stripling said:

 What size heat pump have 🐙 suggested for you? 

Its Daikin 6kW and 180L cylinder.

Same as me.  Great bit of kit. 
Your radiator schedule looks a bit odd. What's happening in the living room? The two suggested don't add up to the heat loss. 

What are you going to do in the bathroom? 

Coming back to the living room question, it looks as if the two radiators together only cover 78% (39% + 39%) of the room heat loss.  The last thing you want is a cold living room so you need to get this rectified.    

Thanks, let me ask them. Could it be the case that the kitchen's radiator is where the kitchen meets the living room and its almost an open plan, therefore compensating for the difference?

FreeBear

stripling said:

@BuildTheWall
They agreed to change the towel rail to radiators for £200 in both bathroom and en-suite. Wondering if that’s worth it. 
They refused any further radiator upsizing changes. 

If you decide to add any radiators your self (or upsize) use a delta T convertor 
You need to take the radiator output at Delta T 50watts (your design temperature) and convert it to Delta T 20watts (which will give you an approximate 40watts design temp).  You can see the final output @ 50 on your radiator schedule.

Methinks that should be a Delta T (∆T) of 50° and 20°C for a flow temperature of 40°C

Looking at the claimed output of a 400x1000mm K2 radiator of 639W, I suspect they are using a design flow temperature of 50°C (a ∆T of 30°). Would be better with a ∆T20°, but that would entail fitting much larger radiators all round (40% larger ?). But for most of the year, the quoted radiators would work just fine with a ∆T20° and you'd only need to turn up the flow temperature on really cold days (think sub-zero).

If I were doing the work, I'd go for 600mm high radiators throughout. But if you've got them under windows, this probably isn't possible.

stripling

@FreeBear
Methinks that should be a Delta T (∆T) of 50° and 20°C for a flow temperature of 40°C  

Lol yes, obviously, my bad. It was late on a Friday. 😁

Looking at the claimed output of a 400x1000mm K2 radiator of 639W, I suspect they are using a design flow temperature of 50°C (a ∆T of 30°). Would be better with a ∆T20°, but that would entail fitting much larger radiators all round (40% larger ?). But for most of the year, the quoted radiators would work just fine with a ∆T20° and you'd only need to turn up the flow temperature on really cold days (think sub-zero)@FreeBear
Looking at the claimed output of a 400x1000mm K2 radiator of 639W, I suspect they are using a design flow temperature of 50°C (a ∆T of 30°). Would be better with a ∆T20°, but that would entail fitting much larger radiators all round (40% larger ?). But for most of the year, the quoted radiators would work just fine with a ∆T20° and you'd only need to turn up the flow temperature on really cold days (think sub-zero)

What I suggested is tried and tested not theory. This is how it worked for those who want to know:

Octopus radiator's output are in the schedule at Delta T 50 which is how the output of the majority of radiators are sold (except the awkward dinosaurs who still only offer BTU outputs & one company that actually mentions heat pumps). I checked all my 🐙 radiators on the manufacturer's own spec sheet before my installation. I also used this method to buy my bathroom radiator which is small (gorgeous design 😁)  but kicks out the heat at really low flow temperatures. 

Thus to get your output at 40º flow temp you run it through that calculator I linked to at 20º which then neatly gives you the output of radiator you need. You check that against the room heat loss until it matches or is higher.  I learned this from Heat Geek and then put it into practice in my own house. 

Having completed a cold winter with my heat pump I can confirm that the radiators & flow temperature were fine. It ran @ 39/40° 'design temp' all winter without using a thermostat - just Leaving Water Control (Daikin's name for 'pure weather compensation'.  I programmed a -2°  drop/set back @ 11pm; a return to 0º @ 7am; and +1° at 4pm. 

The flow temp is adjusted automatically by the heat pump according to the outside air temperature. I don't touch it.  It's the best way to run a heat pump - much less strain on the compressor.  Of course, if you want to buy even more powerful rads you can run your system even lower & cheaper. Think in terms of water volume or radiator 'acreage' - generally speaking, the more you have the cheaper your system is to run. 

It is unhelpful to recommend radiator dimensions because output is what matters and dimensions are relevant to each person's property.  I only needed one K3 but by painting it exactly the same colour as the wall it sits on it has 'melted in' to the background. 

Can't believe I just spent my coffee break prattling on about radiators! 🤦🏻‍♀️😂

BuildTheWall

I just realised its not the Daikin, but their own branded Cosy machine. 
Online reviews are poor. 

I also asked for a quote from Aira. Got quoted super expensive at £7k! They did offer to reduce to £6.5k if radiator replacements are excluded. 
Octopus is £3.2k including 7 radiator replacements. 

stripling

BuildTheWall said:

I just realised its not the Daikin, but their own branded Cosy machine. 
Online reviews are poor. 

I also asked for a quote from Aira. Got quoted super expensive at £7k! They did offer to reduce to £6.5k if radiator replacements are excluded. 
Octopus is £3.2k including 7 radiator replacements. 

There's lots of very happy Cosy owners in the 🐙 (unofficial) Facebook group so you can ask them for feedback. There's also lots of Daikin owners in the group. It's a good group so I recommend joining.  But I'd be wary of asking anyone for Cosy opinions who isn't an owner.  The engineer who designed the Cosy had a company called Red before he joined 🐙 which was very highly rated by heat pump geeks. Me, I like my Daikin. 

I believe you can ask for a Daikin from 🐙 if you prefer. I did! 

I like the aesthetic of the Aira and that's it. I definitely don't like the financial set up at all. I also like the Vaillents but they're above my pay grade.