exploring options

[Stones]

When I've done capital and running cost comparisons in the past, I've found that if your DHW and heating requirements are below 2500kWh/yr each, then Direct electric is the cheapest and simplest way to go.  As the requirement for either rises, so does the balance towards another form of heating.  One thing to remember factoring in with gas is the cost of getting a mains connection AND an annual maintenance contract.  The cost of the connection alone could significantly alter the equation / pay for solar PV.

[ProDave]

2 hours ago, Hecateh said:

Is ASHP expensive to install?

What are you doing for DHW? 

It's no harder, probably easier in fact than a normal system boiler.  Some plumbers may shy away believing it to be complicated.

 

The expensive myth comes from the fact that in order to claim the RHI subsidy, you must have it installed by an MCS registered installer, who for some reason seem to charge a lot more than an ordinary plumber might (my plumber friend paid in the order of £10K supply and fit for his ASHP and HW tank).  With a well insulated modern house it is doubtful of the RHI payments would even cover the extra cost of employing an MCS registered installer.

[Hecateh]

11 hours ago, Nickfromwales said:

think I'd put UFH on both floors TBH, with room stats in each space for the ground / sleeping quarters, and a single room stat for overall control upstairs. I'd also fit two manifolds, one up and one down

Ground floor is lounge kitchen and the bedroom and dressing room upstairs

[Hecateh]

3 hours ago, Stones said:

When I've done capital and running cost comparisons in the past, I've found that if your DHW and heating requirements are below 2500kWh/yr each, then Direct electric is the cheapest and simplest way to go.  As the requirement for either rises, so does the balance towards another form of heating.  One thing to remember factoring in with gas is the cost of getting a mains connection AND an annual maintenance contract.  The cost of the connection alone could significantly alter the equation / pay for solar PV.

Is it reasonably easy to work out what my likely requirements are?

I certainly can't base it on where I am now - this place is a leaky as a sieve

 

Edited January 5, 2018 by Hecateh

[SteamyTea]

1 minute ago, Hecateh said:

Is it reasonably easy to work out what my likely requirements are?

You can work out your domestic hot water (DHW) from your existing usage.

Or start from scratch with a jug, a stopwatch and a thermometer.

 

Your heating requirements should be already calculated for your Standard Assessment Procedure  (SAP, or possibly ESAP, E being enhanced).

If not, you can work it out from the building fabric i.e. what the walls, floors, roofs windows and doors are made from (thermally) and some local weather data.

Bit more involved that that, but imaging that you have a section of wall and it looses 'heat' though it (heat is the old term for energy).  If you know the temperature differences, then you can work out the losses.  The temperature differences change by the hour, so you have to use the weather data to give you the range and frequency (how often they occur) of those temperatures.  This is usually called Heating Degree Days (HDD) and is a crude, but effective method of working out temperature dependent heat losses.

 

Then you need to add to that any ventilation losses, but that is another story.

[Hecateh]

5 minutes ago, SteamyTea said:

You can work out your domestic hot water (DHW) from your existing usage.

Or start from scratch with a jug, a stopwatch and a thermometer.

 

Your heating requirements should be already calculated for your Standard Assessment Procedure  (SAP, or possibly ESAP, E being enhanced).

 

DHW pretty low, about 4 showers per week winter and daily in summer . dishwasher and clothes washer both use cold, probably a bowl of hot water 4 or 5 times a week for miscellaneous pots and cleaning.

Are saps on plans?

[SteamyTea]

SAP stuff should be a separate document.  It may not have been done yet.

 

You may get the water usage, and temperature for your washing machines from the hand books, my Bosch does.  They often have the energy usage too.

 

A 'shower' can be long and hot, short and cool, cool and long or long and short, only you know that.  Why measuring it is useful.

 

 

Mass of Water = Density (or volume) of Water x Flow Rate x Time

 

Energy to Heat Water =  Specific Heat Capacity (SHC) x Mass x Temperature Rise.

 

To use a cooking analogy (and I do a lot of cooking), a small pan of water boils a lot quicker than a large one on the same ring.

In the real world, temperature rise and energy input is not linear.  You loose more energy to the surrounding air the hotter something is.  It is why you may read about storing hot water at a lower temperature.

My DHW system 'lost' more energy over a day that I actually needed to bath in.  So I insulated it more, and it used less. 

 

Just like a thick jumper keeps you warm when it is cold and a windproof jacket helps when it is very windy, the same is true of houses.

Edited January 5, 2018 by SteamyTea

[Visti]

55 minutes ago, SteamyTea said:

...or long and short, ...

 

Schrodinger's Shower!

[SteamyTea]

Best way to deal with a cat.