We should have installed air conditioning… now what?

[Dave Jones]

2 minutes ago, Adsibob said:

What would I need to do that? The lowest tempera setting on my UFH manifolds is 35C.

 

heat pump in reverse.

[SteamyTea]

26 minutes ago, Dave Jones said:

send the cold water through the slab UFH as well.

That is a good idea.

  

1 minute ago, Dave Jones said:

heat pump in reverse.

Whether heating or cooling, they are still heat engines.  The devil is in the demon.

 

Most have settings that can be changed to deliver either hot or cold.

[Wil]

4 hours ago, Adsibob said:

What would I need to do that? The lowest tempera setting on my UFH manifolds is 35C.

 

If that’s the mixing valve, then sending it cold water when it’s expecting hot just means it will fully open and not mix any of the return from the UFH manifold. This is fine as the higher temp return water will just go back to your ASHP/ chiller.

 

If it’s the lowest temp setting to get the manifold circulation pump to engage, that would be strange and definitely a problem for this idea.

 

If you have room stats, you may need to set them excessively high in order to get those zones to open if the temperature in the zone you’re trying to cool is already high.

[joth]

4 hours ago, Adsibob said:

What would I need to do that? The lowest tempera setting on my UFH manifolds is 35C.

You said above you don't have a heat pump?? So first step would be getting one of those. For cooling I'd recommend a2a which really starts back at the top of this thread, doesn't it. 

[Adsibob]

2 hours ago, joth said:

You said above you don't have a heat pump?? So first step would be getting one of those. For cooling I'd recommend a2a which really starts back at the top of this thread, doesn't it. 

I won't be installing a heat pump, having investigated these options at length at the time of design and concluded that the market was crazy. It was much cheaper, and less hassle, to get a highly efficient gas boiler, than go through the process of:

1. getting planning permission to install a more expensive air source heat pump, work out where to put the external unit so that it wouldn't bother us or the neighbours
2. borrowing money to pay for an even more expensive one of these: https://www.ochsner.com/en/ochsner-products/air-source-heat-pump/ (quoted to me at the time as costing something like £15k).

There are space constraints in my property that just make it non-feasible. I hope that prices come down in 15 years time which is when I expect to replace my gas boiler.

 

I know this is environmentally the completely wrong approach, but the government just hasn't incentivised this technology properly and until they do I'm not keen on it.

[JohnMo]

6 minutes ago, Adsibob said:

costing something like £15k

 

7 minutes ago, Adsibob said:

government just hasn't incentivised this technology properly

Not sure the incentive helps, just causes more rip off companies to start up, rip of clients and then close the doors.

 

To buy a 6kW ASHP and the balance of materials can be around £2.5 to 3k, as a priced example a Grant Aerona³ 6kW is £2300 incl VAT (I paid £1300 for different make) plus 2 to 3 days plumbing and a day electrical to install.  So no idea how these companies can justify £15k.

[SteamyTea]

1 hour ago, JohnMo said:

no idea how these companies can justify £15k.

I think that is a zombie number that just won't die.

I heard in the radio the other day that fitting an ASHP can cost up to £14k.

Would be a bargain for some properties.

The only way to get a proper price is to know what you want, then get people to quote for it.

Then laugh at the sily ones.

[joth]

28 minutes ago, SteamyTea said:

I think that is a zombie number that just won't die.

I heard in the radio the other day that fitting an ASHP can cost up to £14k.

Would be a bargain for some properties.

The only way to get a proper price is to know what you want, then get people to quote for it.

Then laugh at the sily ones.

Completely. My 8.5kW ASHP cost £8.5k +VAT design, supply & installed, including MCS cert, supply ErP A 300L cylinder and connecting up UFH and a FCU for cooling. But this number is never the one quoted on here ... 🤷‍♂️

 

[joth]

1 hour ago, Adsibob said:

I won't be installing a heat pump, having investigated these options at length at the time of design and concluded that the market was crazy. It was much cheaper, and less hassle, to get a highly efficient gas boiler, than go through the process of:

1. getting planning permission to install a more expensive air source heat pump, work out where to put the external unit so that it wouldn't bother us or the neighbours
2. borrowing money to pay for an even more expensive one of these: https://www.ochsner.com/en/ochsner-products/air-source-heat-pump/ (quoted to me at the time as costing something like £15k).

There are space constraints in my property that just make it non-feasible. I hope that prices come down in 15 years time which is when I expect to replace my gas boiler.

 

I know this is environmentally the completely wrong approach, but the government just hasn't incentivised this technology properly and until they do I'm not keen on it.

To be clear: I'm not trying to argue you should rip out the functioning boiler and put in and ASHP. My point was that's what the previous few posts seemed to incorrectly assume you already had done.

If you're going to install anything, I'd recommend an air to air heat pump aka air-conditioning unit in the specific room(a) that need it 

[Adsibob]

1 hour ago, joth said:

To be clear: I'm not trying to argue you should rip out the functioning boiler and put in and ASHP. My point was that's what the previous few posts seemed to incorrectly assume you already had done.

If you're going to install anything, I'd recommend an air to air heat pump aka air-conditioning unit in the specific room(a) that need it 

Thanks for clarifying. Yes, I think I’m going to install that, but only if installing the external blind on the Velux first doesn’t make a big difference.

[Adsibob]

3 hours ago, JohnMo said:

To buy a 6kW ASHP and the balance of materials can be around £2.5 to 3k, as a priced example a Grant Aerona³ 6kW is £2300 incl VAT (I paid £1300 for different make) plus 2 to 3 days plumbing and a day electrical to install.  So no idea how these companies can justify £15k.

I can’t remember the size I needed, but the heat loss requirements of my house are about 18kw or 19kw. It’s a large 1930s house that has had insulation added as part of an extensive refurb and extension, but nowhere near passiv standards. And only 2G windows.

Edited March 8, 2023 by Adsibob

[Adsibob]

On 10/07/2022 at 09:13, Omnibuswoman said:

We are now mulling whether to add a velux external awning or external roller shutter to the only Velux window in the attic (West facing). I think that decision will be made only once the house is built and we have had a chance to see how comfortable or not the house/attic feels.

Hi @Omnibuswoman, also wondering whether you ever made this decision? My understanding is that the advantages of the roller blind is it excludes 90% to 95% of the solar gain, whereas the awning only does about 75%, but the disadvantage of the roller blind is that when the roller blind is closed to block out the heat the amount you can open it for ventilation is severely restricted. You can still get a little ventilation, but not much.

Both my velux roof windows are east facing, so solar gain is mainly an issue from an hour or so after sunrise until about noon or 1pm. So maybe I should go for the roller shutter, and automate it with the Netatmo thingy to shut out the sun completely from sunrise to 1pm, then open up completely to provide ventilation. But it's quite a big decision, so curious to know whether you made it and how you've found it.

[Russdl]

1 hour ago, Adsibob said:

from sunrise to 1pm, then open up completely to provide ventilation.

Preventing the heat getting in is a great plan, but don’t open up to ventilate until the outside temperature is below the required indoor temperature. 
 

If it’s pushing 30 degrees outside after when you open up to ventilate it will soon enough be pushing 30 degrees inside and your shading would have been for nought. 

[Adsibob]

3 minutes ago, Russdl said:

Preventing the heat getting in is a great plan, but don’t open up to ventilate until the outside temperature is below the required indoor temperature. 
 

If it’s pushing 30 degrees outside after when you open up to ventilate it will soon enough be pushing 30 degrees inside and your shading would have been for nought. 

Thanks @Russdl. Yes, I currently try and do this and have external temperature data from our Brink Flair 400 MVHR machine which I use for deciding when to do that. The issue I will have is how to integrate that temperature data for automating this. Velux smart kit Netatmo can apparently speak to Apple Homekit so that may be one option (although I don't currently use Apple Homekit, I could given I'm an iphone user and have other mac devices as well). Another possibility is to rely on the Netatmo's ability to consult local weather forecasts, though I do wonder whether those are accurate enough. Anyone have any experience with automation of these windows/blinds through Velux Netatmo?

[JohnMo]

Simple automation 

Close blinds every morning or just don't bother opening them.

 

Is it hot outside leave window closed, is it cooler outside than inside open for ventilation. Do you need automation - no

 

We have Netatmo cameras, complete pain to setup, loose internet frequently. Just wouldn't be a company of choice for me.

[Adsibob]

@JohnMo you make me laugh. That's not automation. That's do it yourself. We like to have the ventilation from the velux at night and I'm not getting up at the crack of dawn to close the roller shutters and close the window. Will research how reliable Netatmo for Velux is. We have good wifi so I'd be surprised if there was an issue, but you never know.

[JohnMo]

So your window is either open and blind has to be open also or blind closed and you cannot open window - that is cr@p design. So on a summer night you go to bed and its still light, cool outside but you have to make a choice - make it dark but hot in bed or still light and cool in bed?  We had Velux windows years ago, we just had a fitted blind inside so you could do both (close out light and open for ventilation) - things moved in the wrong direction.

[Adsibob]

5 minutes ago, JohnMo said:

So your window is either open and blind has to be open also or blind closed and you cannot open window - that is cr@p design. So on a summer night you go to bed and its still light, cool outside but you have to make a choice - make it dark but hot in bed or still light and cool in bed?  We had Velux windows years ago, we just had a fitted blind inside so you could do both (close out light and open for ventilation) - things moved in the wrong direction.

I think both with the Netatmo automation you can control both opening and closing of the roller shutter and of the window. So if I've understood it correctly (and that's a big IF right now):

• at night we could go to bed with the roller shutter open (as there is no solar gain after 1pm on that side of the house) and the window open as it would be desirable to have ventilation over night
• we could set it to close the roller shutter and close the window at sunrise.

What would be particularly good if there is sufficiently detailed control to allow the roller shutter to close at sunrise, but the window to remain slightly open, so ventilation continues until the outside temperature reaches a certain level. For that, I need someone who owns this setup to volunteer their experience.

[marshian]

On 19/06/2022 at 13:58, Adsibob said:

Just had a look at temperatures: the second floor rooms are currently 23.6 and 23.5 whereas the rooms directly underneath them are both 23C. So maybe it is more solar gain than internal heat, no idea really. Outside it’s currently 18C, although that’s based on the bbc as I don’t have an external thermometer.

do you not have an external temp sensor (for WC) on your boiler?

[Russdl]

Alternatively, find the nearest location to you on the Weather Underground map

 

 https://www.wunderground.com/dashboard/pws/ILONDO538

 

and that will be a personal weather station near you, probably in someone’s back garden, and that should give you a better idea of the local air temperature. 
 

if the temperature defaults to F you can change it to C, settings are accessed via the three bars, top right corner. 

Edited 14 hours ago by Russdl

[Adsibob]

11 hours ago, marshian said:

do you not have an external temp sensor (for WC) on your boiler?

No.