My head is aching

[MiriPiri]

Hi,

 

I am buying buying a 1950's ex council house in North East Scotland.  It currently has the original open fire with a back boiler, double glazing, no extra insulation, immersion  heater and an oil tank with a fairly new boiler.

 

I would really like to update the whole system, but my head is just exploding at all the options.  The house is south facing so solar panels are an option.  I'm wanting to replace the open fire with a log burner so do I go biomass for the heating/DHW or have a traditional log burner and an ASHP?  I started reading through a few threads on here and came across Sunamp and Wallis heaters just to add to the confusion.  Are heat pumps good or are the government pushing them to boost the industry re jobs etc?  Is it worth getting an electric combi boiler?  I am open to all and any options. Please help.

 

How do I choose a system that is as integrated as possible whilst also being environmental and affordable?  My head is aching with information overload and anxiety about making the right choice.  Any advice would be great please.  The only thing I do know is that I need to improve the heat loss ASAP.

[Mr Punter]

31 minutes ago, MiriPiri said:

The only thing I do know is that I need to improve the heat loss ASAP.

+1

Insulation and airtightness need to be the priority.  Spend most of your budget on this.  If the oil boiler works OK, stick with it for now.  If it does not heat the water, use the immersion.  Forget the Sunamp and the log burner.  Close up the fireplace.

[Iceverge]

My mantra for proceeding. 

 

1. Sort any bulk water issues.

2. Ventilation (preferably continuous mechanical, ideally with heat recovery)

3. Airtightness (cheap and hugely effective)

4. Improve u values.  (Including windows) 

5. Consider your heating system. 

6. Renewables (PV)

 

 

[JohnMo]

I think ASHPs are good if you have a low energy home, but even then you at looking £10k install, (more with a high energy home) with grants you could half this.  You will need bigger radiators as the temperature developed by heat pumps is lower than oil or gas.

 

Heat pumps when optimised develop approx 3kW heat for each kW of electrical energy, but electricity cost 3 times that of gas, but not sure about oil.  Oil boiler nearly produces a kW heat for each kW of energy put in.

 

As everyone has said insulation is king, keep the heat in.

 

Ventilation, part of your heat loss calcs is ventilation heat loss, an old house could have 10 or more uncontrolled air changes an hour, each of these air changes needs to be heated.  An airtight house has 1, or less air changes per hour, that require heating.

 

We have solar panels, but they only really produce lots of energy in the summer, if can get some gains in winter via an immersion heater that is good, but don't bank on it in a heating design.

 

My recommendations are

Find or build a spreadsheet, work out room heat loss as it is now, then modify spreadsheet with different options also look at costs.

 

The more you move from what you have now, the more the cost, especially if you have someone else to do the work.

 

In NE Scotland there is scheme running to apply external insulation, my wifes sister also in an ex council house has just had done for next to nothing, this included re rendering the external of the house.

 

Insulation and fix drafts.

 Get a basic diagnostic air test done, this will highlight areas where you are leaking, to see if they expensive to fix or otherwise.  There's a guy in Forres that does tests.

Find out if you have a condensing oil boiler, if so optimise return temps from heating to a low 40 degree C, so it runs in condensing mode.  This may require larger radiators to give the right output in to room, but much cheaper than biomass or ashp

Look at your water cylinder check the insulation, my be worth keeping or replacing.

 

Overall keep it simple

 

 

 

[SteamyTea]

Regardless of the heating system, heat losses and maximum heat demand will be the same.  You can't fool nature.

The reason that the government is pushing heat pumps is that they are the only practical way to supply thermal energy to home in a low CO₂ emissions manner.  This is because we are cleaning up our electricity generation.  This is expensive, hugely expensive, but in the last decade we have reduced that sector emissions 5 fold.

There is an alternative to use resistance heating, like we did between the 1960's and the late 1980's.  This would mean we would have to add a lot more generation capacity.  This is possibly cheaper, in the short term, than retrofitting heating systems.  But there is a land issue.  The UK does not like having wind turbines and solar farms on its land.  We have convinced ourselves that only the best farming land will be used for this, will kill every bird within a mile of a turbine and the glare from a solar farm will give every child cataracts.

It is all bollocks of course, but perception is more important than fact.

So it is basically down to us to upgrade our homes.

 

If your roof is suitable for PV, add it.  It is cheap to self install and could probably do 70% of your DHW needs (with some diverter trickery)

Airtightness and insulation really need to be considered together.  External wall insulation is usually the most cost effective and will (should) improve airtightness.  It is like putting a windproof winter jacket on.

There will always be areas that air can bypass this that may have to be address after the installation.  This may well be hard to get at area i.e. between loft space and the rooms below.  These can possibly be addressed when fitting PV as scaffolding will be on site.

Ideally you would convert your roof void to a warm roof system, then mechanically ventilate your house.  This is expensive.  So go down a layer and make the interface between room ceilings and loft space airtight, then ventilate the rest of the house.

 

Some internal insulation may be useful.  The ground floor is a large area, that is usually connected to the ground, which is cold.  Insulating the floor will help a lot.  This is not always easy as door and ceiling heights are important, as is the first step on the staircase.  Digging up the existing floor, adding in 200mm of insulation, screen and UFH pipework is not really a viable option.  But 20mm of insulation will help.

 

Now back to ventilation.  You have probably read that systems with heat recovery are not effective unless the ACH are below 3.  I have never calculated this, but it intuitively make sense.  So get the airtightness sorted out.  It is more important than having a wall U-Value of 0.1 W.m^-2.K^-1.  Fitting MVHR is a bit disruptive as it usually requires boxing in some pipework between floors.  This does depend on the house layout.  Through the wall systems are available, but they are not as efficient as proper systems, but are cheaper.

Ditch any thoughts of a log burner.  All these do is add CO₂ to the atmosphere (what we are trying to avoid), put holes in your walls and roof (what we are trying to avoid), fill the house and street with particulates (there is new WHO guidance on this), cost a lot to run and smell.

 

Fitting an ASHP is probably the easiest option if you have room for radiators (really convectors), but plinth heater can help in tight spaces.  All these are, are fan heaters, with the heat coming from hot water, rather than an electrical element.  I have no idea how noisy they are in a domestic setting, only experienced them in offices, where I never noticed them.

 

The main thing is to not be tricked into thinking that there is some wonder technology that will sort it all out, cost less to install, have zero running costs and the government will pay for it all, and reduce your income tax to 10p.  So if you hear the terms Far Infra Red, Reflective, Nano, Eco, Sustainable, Multifoil, Easy, or other such nonsense, laugh at them and walk away.

 

  

16 hours ago, JohnMo said:

Overall keep it simple

 

Yes

Edited October 21, 2021 by SteamyTea

[Ferdinand]

You haven't told us unless I missed it whether your floor is solid or suspended.

 

Given where you are I would suggest a bit of evaluation on the solar panels before fitting.

[MiriPiri]

Hi everyone, thank you so much for all the detailed replies. A lot to think about and read up on. I’ve never heard of external insulation.

 

so, insulation, ventilation and airtightness first and if there’s any money left over go for PV then ASHP and forget about the log burner ? I do love a fire in the winter. 
 

I’m to Google air diagnostic test now …

[Iceverge]

ventilation 

airtightness 

insulation 

 

in order. you could have issues with moisture otherwise. 

 

2 hours ago, MiriPiri said:

air diagnostic test now …

 

make your own rig, a sheet of OSB or plywood and a car radiator fan connected with some wires to a car battery.