This old house... time to upgrade

[Crofter]

Not my first thread on this project but I figured I would start again from scratch.

 

I have a 93m² bungalow, 1970s double block with suspended floor. NW Scotland, fairly cold and exposed, no mains gas. No severe frosts.

 

Currently on the Total Control tariff, which gives 24/7 access to cheaper electricity for heating and DHW, and a higher rate for everything else. This tariff is not especially good value (the rates last time I checked were 24/37p). This tariff is set to be phased out soon anyway.

 

Currently I have storage heaters and a direct UVC.

 

The house is primarily used in the summer only, as a holiday let. We do get occasional out of season visits.

 

We're going to spend next summer in the house ourselves, which gives me a chance to do something about the heating. I don't think storage heaters are a good fit for a house that lies empty for weeks at a time, and is often empty during the day even when guests are staying. We have no way of controlling the heating remotely, and most people don't understand storage heaters so it's pretty common to find everything turned right up. 

 

I'm swaying towards a ducted A2A system with a WiFi controller option, so that we can keep an eye on things and adjust the heating while the house is empty. But I'm assuming that will work best with a flat rate tariff, not E7?

 

Which leads to a problem with the DHW. I don't have numbers, and usage is variable, but clearly DHW is a big part of the energy use, and it would be a shame to no longer get an off peak rate for that.

 

I'm certainly interested in fitting PV plus a diverter to help heat up the tank, but that's going to be quite intermittent and of almost no help over the winter, not that there is much usage then.

 

Anyway, I'd really appreciate some feedback on this rough plan. It's going to be a lot of work and, with no grant available on A2A, a fair chunk of money too. As always with my projects, I plan to do as much of the work as possible myself.

 

 

 

Tl;dr: what space heating + DHW system would you suggest for a house used for short term lets, mostly over summer. Needs to have both an idiot proof user control, and ideally a remote option.

 

 

[Crofter]

Ah come on, somebody must have an opinion on this... 😁

[Jilly]

I would spend money draught proofing and insulating the house, and then leave very clear instructions on how to use the storage heaters…

[Iceverge]

I assume you've taken care of the fabric - Airtightness , insulation and ventilation?

 

I would consider throwing any money I had into PV and diverters. As your usage is mainly summer months you can divert any excess juice to the DHW and then the Storage heaters pretty easily. 

 

Maybe an infrared heater for the bathrooms on a push 15 minute timer to make showering nicer would be cheap enough too. 

 

 

 

 

 

[Crofter]

45 minutes ago, Jilly said:

I would spend money draught proofing and insulating the house, and then leave very clear instructions on how to use the storage heaters…

It doesn't matter whether you tell people, they still need to think ahead by 24hrs which they won't do. And they're not paying for the electricity so they don't really care anyway.

 

I've made some improvements on fabric, and will continue to do so.

[Crofter]

16 minutes ago, Iceverge said:

I assume you've taken care of the fabric - Airtightness , insulation and ventilation?

 

I would consider throwing any money I had into PV and diverters. As your usage is mainly summer months you can divert any excess juice to the DHW and then the Storage heaters pretty easily. 

 

Maybe an infrared heater for the bathrooms on a push 15 minute timer to make showering nicer would be cheap enough too. 

I'm kind of waiting to see what happens with Octopus and the non-MCS export deal they were doing.

But yes that could make a lot of sense. Still doesn't solve the remote monitor/control question.

 

I'm pretty much sold on installing A2A but not sure if the numbers really stack up if I lose the off peak DHW rate.

[ProDave]

4 minutes ago, Crofter said:

but not sure if the numbers really stack up if I lose the off peak DHW rate.

Your "cheap " rate seems to be 24p per kWh but the penalty is 37p at other times.

 

the standard Octopus single variable rate is 27.26p

 

So you are saving barely 3p per kWh for your cheap rate but paying 10p extra at other times.

 

Go to a single rate, fit your A2A heating, and some solar PV just for self usage.  Do as much of your heating and big loads like WM etc in the daytime and dump any surplus PV not already used to water heating via an immersion and a solar PV diverter.  No need for export or any export payment.

[SimonD]

7 minutes ago, Crofter said:

Still doesn't solve the remote monitor/control question.

 

Would Shelly relays suffice?

[Crofter]

5 minutes ago, SimonD said:

 

Would Shelly relays suffice?

I may have to Google that.

Key thing is that the people in the house need to have idiot proof hardwired controls too.

[ProDave]

Why do you want remote control?

 

For idiot proof controls, I just integrated a standard central heating programmer as the main control, shunning the over complicated timer functions built into the ASHP.  Operating our heating is just the same as operating a central heating system with a gas boiler that most people are familliar with.

 

One function our programmer has is a "holiday mode" where you can turn the heating off for a number of days if you go away, and set it to be back on by the time you get home.  About the only use I can think for remote control.

 

If you are letting, all I would add is room thermostats.  Either fit ones with remote sensors and the actual controller (with the dial) out of reach, or even fit placebo thermostats (for show only)  I speak from experience of running a B&B and finding the room thermostat at 30 degrees, the boiler working it's socks off and the bedroom window wide open to keep it cool.  Some people do some daft things (I am struggling to be polite here) when they are not paying the bills.

[Crofter]

3 hours ago, ProDave said:

Why do you want remote control?

Because I've not set foot near the property for two years and I'm traveling indefinitely, thousands of miles away.

Last time I was home, I found every heater turned up full, despite having instructed the property manager to dial it right back once they last guests of the season had left.

 

I don't really mind people setting it to whatever they want while they are there, it's the unoccupied winter months that concern me. If had remote control of everything, I could be watching the weather back home and adjusting the heating as necessary, to prevent frost damage.

 

The current 'system' has almost no control at all. On the Total Control tariff (a misnomer if I ever heard one) the electricity company decides when the heaters come on. One of the three storage heaters has a basic thermostat control, just a dial on top. And that's it.

 

When we lived in the house we usually turned off the two smaller heaters at the wall, and the single large one we kept turned down as far as we could tolerate. Whilst making a lot of use of our woodburner.

 

With the impending phaseout of THTC, I am forced to do something- there is no way that the current hardware in the house can operate correctly under a different tariff (even if I just switched to E7, I'd have to install timers for each heater). So it seems the right time to upgrade to a modern system that would hopefully cut running costs and allow better control.

[ProDave]

Do A2A heat pumps allow external controls like room thermostats?

 

Perhaps a proper Air to Water heat pump might be better?  It will do your DHW and heating but you will need radiators or UFH.  But at least the HP will have provision for external controls.

 

In this situation I would say the best would be UFH with an individual room thermostat in every room.  Then those room thermostats can be replaced with remote programmable ones.  I installed a system like that at the local community hall, a lot of the time the hall sits empty so they can turn the heating down, and when there is a booking, they can remotely turn the heating up for that.  I forget which remote system it is but I can find out.  It was not one of the popular ones like hive or Nest.

[joe90]

Do you have Wi-Fi?, my place has a “nest” which I can control the heating over the internet, not sure it can control an air to air heat pump tho 🤷‍♂️ 

[Gill]

2 minutes ago, ProDave said:

Do A2A heat pumps allow external controls like room thermostats?

 

My mitsubishi A2A system can be managed remotely. The models I went with have built in WiFi. I find the app clunky - setting timers relies on the app having Internet connection when timers are triggered. Handy for turning on when I'm commuting home or checking / changing temps but not for scheduling in my limited experience. 

Remote controls for each unit - didn't have any need for hardwired control panels . The unit itself does have thermostat and with high wall mounted, it's always reading a few degrees higher than floor level. 

 

 

[dpmiller]

if you've wifi there's plenty of simple automation out there. I got a few cheapo zigbee TRVs recently and they're very good, yes you can override them locally, but programming and resetting on the app is simples.

[SteamyTea]

11 hours ago, SimonD said:

11 hours ago, Crofter said:

Still doesn't solve the remote monitor/control question.

 

Would Shelly relays suffice?

If you initially want to keep the storage heaters (as you have them and you are doing other work), remote control relays should do the trick.  You just reduce the hours they are running to limit the input/output.

 

The only thing I would worry about is how well they deal with a power cut.  Do they reconnect easily and reliably?

[Iceverge]

Where are you with the fabric? 

 

Given it's mostly unoccupied in the colder months you could surely insulate your way out of both the summer heating and winter frost protection problem. 

 

 

 

 

 

[Crofter]

3 hours ago, ProDave said:

Do A2A heat pumps allow external controls like room thermostats?

 

Perhaps a proper Air to Water heat pump might be better?  It will do your DHW and heating but you will need radiators or UFH.  But at least the HP will have provision for external controls.

 

In this situation I would say the best would be UFH with an individual room thermostat in every room.  Then those room thermostats can be replaced with remote programmable ones.  I installed a system like that at the local community hall, a lot of the time the hall sits empty so they can turn the heating down, and when there is a booking, they can remotely turn the heating up for that.  I forget which remote system it is but I can find out.  It was not one of the popular ones like hive or Nest.

I did start looking in to a wet system but it's obviously going to be a much bigger job than A2A, especially UFH. We have suspended pine floorboards so I think I'd need those aluminium plates. Big job.

I've got about six months to do all if this, whilst working full time, and doing a bunch of other projects. So I'm a bit cautious about how much I can realistically achieve.

[Crofter]

3 hours ago, Gill said:

 

My mitsubishi A2A system can be managed remotely. The models I went with have built in WiFi. I find the app clunky - setting timers relies on the app having Internet connection when timers are triggered. Handy for turning on when I'm commuting home or checking / changing temps but not for scheduling in my limited experience. 

Remote controls for each unit - didn't have any need for hardwired control panels . The unit itself does have thermostat and with high wall mounted, it's always reading a few degrees higher than floor level. 

 

 

So if you don't have internet, your heating won't come on 🤔😬?

Or will it revert to whatever it was last programmed to do?

I do have internet most of the time, but it's not guaranteed.

[Crofter]

2 hours ago, SteamyTea said:

If you initially want to keep the storage heaters (as you have them and you are doing other work), remote control relays should do the trick.  You just reduce the hours they are running to limit the input/output.

 

The only thing I would worry about is how well they deal with a power cut.  Do they reconnect easily and reliably?

I don't really need an interim solution 

I get back to the house in May and will be living in the house myself over the summer. By the time I leave in November I want to have everything set up with all the improvements.

 

Hopefully OVO Energy will not shut down the THTC tariff before I get back. I'd be hoping that it would up to them to think up a solution for the fact that they can't just get rid of my tariff and leave me with a functioning heating system.

[Crofter]

17 minutes ago, Iceverge said:

Where are you with the fabric? 

 

Given it's mostly unoccupied in the colder months you could surely insulate your way out of both the summer heating and winter frost protection problem. 

 

What you're saying is pretty much how the smaller property operates. It doesn't have or need a heating system, and the background heat from the UVC is enough to keep the place warm enough to avoid frost or damp problems.

 

On the house in question, we have the cavities filled, loft insulation up to 270mm, doors and windows replaced with a mixture of 2+3G. Underfloor partially insulated and I will add to this as my first step when I get back.

 

We have quite a long season- basically full from early April to late October, which takes you well in to the colder months, but we get out of season bookings too. We have some people coming in next week, for example. And of course usually booked over Christmas and New Year.

 

With no remote monitoring or control, and a busy property manager who hasn't historically been great at little things like adjusting the heating, I'm very keen to be able to keep an eye and make changes remotely.

[Iceverge]

Sound not too bad. 

 

If you were to finish the suspended floor and really work on the airtighess it'd help. 

 

 

 

Being a similar climate to Ireland I imagine keeping a handle on the dampness is vital. Maybe a PIV or some dMEV fans might make it "feel" warmer. 

 

 

[Gill]

1 hour ago, Crofter said:

So if you don't have internet, your heating won't come on 🤔😬?

Or will it revert to whatever it was last programmed to do?

I do have internet most of the time, but it's not guaranteed.

 

I can't control away from home without Internet. Timers I've previously set using the remote continue to work as does normal remote control operation. It's a strangely disjointed system where the remote offers ability to set 4 schedules a day which must be stored on the unit. The app is simply hitting an api at times programmed into the app - if my router is offline (or mitsubishi cloud was down) it won't work. 

[Crofter]

3 minutes ago, Gill said:

 

I can't control away from home without Internet. Timers I've previously set using the remote continue to work as does normal remote control operation. It's a strangely disjointed system where the remote offers ability to set 4 schedules a day which must be stored on the unit. The app is simply hitting an api at times programmed into the app - if my router is offline (or mitsubishi cloud was down) it won't work. 

So if I'm understanding correctly, you set up four different schedule options, and use the app to move from one to the other? And if you're offline, it'll just continue with whatever schedule it's on?

[Crofter]

If I go ahead with an A2A+UVC system, perhaps with PV+diverter, any thoughts on:

a) flat rate vs E7?

b) any special tariffs that might be better?

c) trying to run the A2A overnight rather than on low 24/7?