New build - heat and energy considerations

[joe90]

13 minutes ago, ProDave said:

There is talk (it may even have happened) of domestic rentals requiring a legionella risk assesment.

 

We recently rented out our last house through an agent and there was no mention of that.

[Ed Davies]

37 minutes ago, A_L said:

No references, but 70°C is the usually quoted output temperature

Thanks, at least it's not just me imagining it. ?

 

So pretty much linear with temperature difference, as you'd more or less expect.

[Tyke2]

30 minutes ago, ProDave said:

There is talk (it may even have happened) of domestic rentals requiring a legionella risk assesment.

 

In your case it could very well be different, it might be open vented cold water storage tanks in relatively warm plant rooms feeding via a calorifier to the hot taps, where the risk may be very very different to my situation.

You are correct. The difficulty in dealing with healthcare property is that the regulations are very generic to cover worst case scenario. In many cases it is big overkill. As in reality there is actually no real need to store the cold water on a typical high street GP building.

[AliG]

That's an interesting chart.,  presumably issued by a radiator manufacturer. The radiator is not getting more efficient, it is just outputting a higher percentage of its rated heat output, hence why "efficiency" can get to over 100%

[Tyke2]

26 minutes ago, joe90 said:

 

We recently rented out our last house through an agent and there was no mention of that.

Its not quite black and  white unfortunately.

The HSE guidance is:-

 

The practical and proportionate application of health and safety law to landlords of domestic rental properties is that whilst there is a duty to assess the risk from exposure to Legionella to ensure the safety of their tenants, this does not require an in-depth, detailed assessment.  The risks from hot and cold water systems in most residential settings are generally considered to be low owing to regular water usage and turnover. A typical ‘low risk’ example may be found in a small building (eg housing unit) with small domestic-type water systems, where daily water usage is inevitable and sufficient to turn over the entire system; where cold water is directly from a wholesome mains supply (no stored water tanks); where hot water is fed from instantaneous heaters or low volume water heaters (supplying outlets at 50 °C); and where the only outlets are toilets and wash hand basins. 

 

Interestingly it does refer to a 50 Celsius minimum at outlets.

I don't do anything for my rental properties.

 

[Ed Davies]

1 hour ago, AliG said:

That's an interesting chart.,  presumably issued by a radiator manufacturer.

Nah, just me graphing A_L's helpful numbers.

 

1 hour ago, AliG said:

The radiator is not getting more efficient, it is just outputting a higher percentage of its rated heat output, hence why "efficiency" can get to over 100%

Yeah, “efficiency” is a rather badly chosen word. As you say, I just meant the output as a percentage of the rated output.

 

But that does bring us back to AliMcLeod's question about what temperature to run upstairs radiators. Given that it's off a gas combi in their case it probably doesn't matter that much but off, say, an ASHP it would be nice to estimate the lowest temperature which would give enough output. That seems to me to be one case where weather compensation (automatic or just turn the temperature up manually when it gets cold) might be useful.

[Jeremy Harris]

Slightly off topic, but we did a fair bit to improve the thermal efficiency of our old house, which had conventional gas central heating with radiators under practically every window.  After adding another 150mm of loft insulation, going around sealing up literally hundreds of tiny air leaks (mainly at the wall to ceiling junction, where there were barely visible gaps), installing 60mm of bonded EPS bead cavity wall insulation and replacing all the old timber windows and doors for reasonably good 28mm DG uPVC ones, I found that I could turn the temperature of our boiler down to about 45 deg C and it would still heat the house in cold weather.  During one very cold spell I had to turn it up to 50 deg C, but I'm pretty sure I've only done that once.

 

In effect, we've ended up with radiators that are too big for the heating requirement when using a normal boiler heating flow temperature, by a combination of having reduced the heat losses and the fact that I think the original system was a bit over-sized, anyway.  We seemed to have an awful lot of big radiators for a relatively small house.  I'm pretty sure we could have fitted an ASHP rather than a gas boiler and the heating would have still worked well, but with mains gas it's a bit of a no-brainer to fit a condensing gas combi, just to get a decent DHW supply, something that ASHPs will do, but with a hot water tank and reduced efficiency when heating DHW.

[Nickfromwales]

On 11/09/2018 at 16:47, Ed Davies said:

That seems to me to be one case where weather compensation (automatic or just turn the temperature up manually when it gets cold) might be useful.

Weather comp, as your typical generic OEM unit, is quite an arse from my direct experience. Vaillants offering was more like a bloody switch than a real time variable / compensation device  Then I had the added grief of wanting to apply it to a house with a system boiler and GF UFH / FF RADS + UVC which meant when WC kicked in and attenuated the boiler flow the rads cooled down but the UFH became U/S. Ok I thought until they said the s-bus system wasn't clever enough to ramp the temp up when providing DHW to the cylinder via an S-plan. OK again I thought, ill do W plan DHW priority. Nope. Not supported as WC still governed the max flow temp.

I think WC is massively over rated, over complicated, poorly executed and very mis-understood. Good controls are the better investment eg room stats with very short hysteresis, digital not rotary / mechanical, and lashings of user awareness of how and why things do what they do. Most folk still think a TRV on a radiator controls the radiator temp   

 

[AliMcLeod]

1 hour ago, Nickfromwales said:

Most folk still think a TRV on a radiator controls the radiator temp   

 

And that turning a room stat up to higher temperature will make the room heat up faster. 

 

I've given up trying to explain that to my family.

[joe90]

My other half asked when the heating was going to be turned on (ASHP and UFH) I explained I am yet to wire it up (still trying to work it out) and she said “you will have to show me how it works.”  OH NO, if I do that it will be wound right up as soon as I turn my back! She does not get the constant temp thing in a well insulated heavy house. In our last temp house (which had no insulation and leaked like a caravan) the heating worked instantly but it cooled as quickly. This might be an uphill struggle ?

[PeterW]

14 minutes ago, joe90 said:

My other half asked when the heating was going to be turned on (ASHP and UFH) I explained I am yet to wire it up (still trying to work it out) and she said “you will have to show me how it works.”  OH NO, if I do that it will be wound right up as soon as I turn my back! She does not get the constant temp thing in a well insulated heavy house. In our last temp house (which had no insulation and leaked like a caravan) the heating worked instantly but it cooled as quickly. This might be an uphill struggle ?

 

Fit a second stat for her on the wall .... just don’t wire it into anything .... 

[joe90]

1 minute ago, PeterW said:

Fit a second stat for her on the wall .... just don’t wire it into anything .... 

 

Oh i love it!! , funnily I have the Wunda stat in the hallway but found that the command unit can do the same function ?

[ProDave]

4 minutes ago, PeterW said:

 

Fit a second stat for her on the wall .... just don’t wire it into anything .... 

Then she will be complaining it is "not working" as the room has not reached the setpoint of 30 degrees.

 

This is the reason I wanted my heating system operating from a "normal" central heating programmer, not the fiendishly complicated thing that came with the heat pump (that is connected but hidden away in the plant room for parameter setting etc only)

[newhome]

9 minutes ago, PeterW said:

 

Fit a second stat for her on the wall .... just don’t wire it into anything .... 

 

You are a bad person @PeterW!!! Karma gonna get ya!

 

I’m sure Mrs @joe90‘s contact details must be somewhere! ?

 

 

[Triassic]

27 minutes ago, joe90 said:

she said “you will have to show me how it works.”  OH NO, if I do that it will be wound right up as soon as I turn my back!

I’ve had the same problem with an accommodation block on a Scout camp site. Occupants would turn the wall stat up to maximum out of habit. After months of trying to set a nice temperature, only to find someone had fiddled with the room stat yet again, we disconnected it and fitted a hidden stat to control the temperature. The upshot was we never got complaints about being cold and the occupants could fiddle with the room stat to their hearts content.

[Tyke2]

On ‎11‎/‎09‎/‎2018 at 14:51, joe90 said:

 

We recently rented out our last house through an agent and there was no mention of that.

 

6 minutes ago, ProDave said:

Then she will be complaining it is "not working" as the room has not reached the setpoint of 30 degrees.

 

This is the reason I wanted my heating system operating from a "normal" central heating programmer, not the fiendishly complicated thing that came with the heat pump (that is connected but hidden away in the plant room for parameter setting etc only)

My wife puts her hand on a radiator and if it doesn't blister her hand it means that the house is cold and the heating isn't working, so she winds the stat up.

Also if I go in the shower after her or my daughter and don't check the temp control, its like being blasted by scalding needles.

 

[joe90]

Oops, what have I started, seems a common theme tho ? when her son comes to visit he throws open all the windows exclaiming how nice the air feels (in a T shirt).

[Tyke2]

I sit in the house in T-shirt , wife n daughter have onesie and hot water bottle. 

[Triassic]

9 minutes ago, joe90 said:

when her son comes to visit he throws open all the windows exclaiming how nice the air feels (in a T shirt).

My wife does the same, she describes it as a "hot flush"! whatever that is!!!

[newhome]

17 minutes ago, Tyke2 said:

Also if I go in the shower after her or my daughter and don't check the temp control, its like being blasted by scalding needles.

 

I’m with you there. I could never understand how the hubby could shower in stupidly lukewarm water. Unless it’s hot it doesn’t work for me. I always have to override the safety thing on the controls and click it above the level that’s supposed to be considered safe. That’s cold! 

[newhome]

8 minutes ago, Tyke2 said:

I sit in the house in T-shirt , wife n daughter have onesie and hot water bottle. 

 

I was talking to a guy at work yesterday. I said that I was thinking of putting the heating on as it was circa 18.5 - 19 degrees in the house now and I prefer the living space to be 20. He said he would have the windows open at 20 lol, he prefers 16. Horses for courses ?

 

 

[ProDave]

17 minutes ago, Triassic said:

My wife does the same, she describes it as a "hot flush"! whatever that is!!!

As a Husband, you will learn in due course what a "Hot Flush" is.

[Hecateh]

2 hours ago, PeterW said:

 

Fit a second stat for her on the wall .... just don’t wire it into anything .... 

Sometimes I'm really glad I live alone

 

Re the thermostat up to the top though - I don't do that and was forever trying to persuade people at work that it didn't help

[Onoff]

1 hour ago, ProDave said:

As a Husband, you will learn in due course what a "Hot Flush" is.

 

I think I've hit the manopause...

[newhome]

1 hour ago, ProDave said:

As a Husband, you will learn in due course what a "Hot Flush" is.

 

It means STFU and don’t pass comment on anything, least of all complain about windows being open at that point or otherwise! ?