Hive Thermostatic control or not?

Calibos

Not sure if this would be the correct forum because its not a technical issue with my plumbing or heating but is kind of about my Hive Multizone Thermostat setup.

Self installed a Hive Multizone hub/controller/thermotstats during the Summer with the help of the ever helpful and ever patient DGOBS. It replaced a faulty Sunvic 307 that was HW+2 Heating Zone Timer control only. Our usage pattern of the Sunvic for the Heating zones was to boost for 3 hours as needed when the weather was mildish in Autumn/Winter/Spring but for sustained cold spells we'd activate the time slots of 7am till 10am and 4pm till 9pm with boosts before and after if it was really cold, external doors opened a lot etc.

So October rolls around and its time to see what this new Hive can do. I set a target temp of 20º for Downstairs and 19º for upstairs with a single timing zone of 7am - 12am downstairs and 7am - 9pm upstairs. I have the app page bookmarked in my browser and I pretty much check house temps several times a day in the app and its always close to the target temp upstairs and downstairs and the boiler hardly ever seems to be on. (The room my PC is in is beside the Boiler cupboard so I hear it going on and off) I've checked the temp logs in the Hive app and that also seems to back up my impression that the Boiler is hardly ever on because the temperature of the house only drops on average 0.5º or rarely 1.0º from when the heating shuts off completely for the night at midnight and comes back on in the morning at 7am. So it stands to reason that if the house only cooled 0.5º in 7-8 hours overnight then the boiler would only rarely need to come on to top the temp back up the half degree to the set target temp during the active thermostatically controlled active timezone.

.......and yet......

My October/November Gas bill was €100 more than the same period in 2017 or 2016 when it was controlled by the Sunvic timer, 3 hour boosts and wasted heat when it got too hot and people opened doors to cool the house back down to a comfortable temp.

It was an estimated bill despite me submitting a reading myself just before the end of the billing period. Just submitted another one tonight. I know it'll all balance out but it got me thinking. How in hell am I supposed to work out whether my Hive as currently setup is saving me money or costing me money if Bord Gais won't use my meter readings and their estimated usage is up and down and all over the place from bill to bill. Theres no point in adding up the heating season bills to compare with previous years because any variance in the weather compared to the previous year will likely always mask the much smaller per month potential savings or extra cost of running 14 hours a day thermostatically controlled as compared to using boost only or using multiple timezones with or without boosts etc etc. For example, we used 6000 kwh more this year than last year. Only started using the heating with Hive in Oct/Nov but any savings or extra cost running it the way I did compared to the Sunvic the previous year was swamped by the extra cost incurred Feb/March because of the Beast from the East and all that snow.

Cerco

IMHO the only way you can compare it is by the kWh meter readings. You can use the rates then from your bill to estimate the costs.
The price of gas has increased and estimated bills make year to year comparison difficult as you say.
Forecasts suggest we may have another beast from the east so we may have a sharp cold spell.

Calibos

Cerco wrote: »

IMHO the only way you can compare it is by the kWh meter readings. You can use the rates then from your bill to estimate the costs.
The price of gas has increased and estimated bills make year to year comparison difficult as you say.
Forecasts suggest we may have another beast from the east so we may have a sharp cold spell.

Weather forum regular like meself I gather Looking like if anythings going to happen it'll be late January at the earliest as the Sudden Stratospheric Warming is only starting to interact with the Troposphere now and theres a few weeks lag before we'll know if and where the Polar Vortex splits and if Ireland will potentially get in on the action.

I had the calculator and online bills out last night and was able to work out a potential bill for Dec/Jan based off my late November and last night meter reading. I mean it does look like the bill will be about €100 less than it often is and balance out the Oct/Nov bill that was €100 more than it often is but as we know, there is no conclusions that can be drawn about my Hive settings affect on things because some Dec/Jan bills were lower due to estimations and rebalancings while I'm sure others were lower due to mild Dec/Jan's in the past.

However, I now understand what you mean about ignoring the bills per say and just concentrate on kwh for the purposes of deciding on Hive settings. Thanks for that. I can be a dumdum at times!

So in 7 days time I'll take another meter reading to compare to last nights. That'll be my consumption with the Hive as currently set with 12am-7am OFF period and 7am-12am Thermostatically controlled ON period with its target temps of 20ºc downstairs and 19ºc upstairs. Then next week I turn the heating Schedules OFF and just let people boost the zones as they feel the need and tell them to boost for 3 hours like they used to do with the Sunvic 307 with a Target of 24ºc which will mean the heating stays on for the duration of the boost like it would have on the Sunvic. Then 7 days later take another meter reading and compare the kwh used to the previous week.

Boom! in a fortnight I'll know if the Hive thermostatically controlled settings are both more comfortable with no extreme temp swings and saving us money or at least cost neutral....or....I find that a couple of full on boosts every day is more efficient for our particular family/home/usage patterns. Even if the latter turns out to be the case, its not like I wasted money on the Hive. Thanks to being able to self install with DGOBS help and getting it on Sale, the Hive Multizone setup only cost me €100 more than a replacement Sunvic 307 would have and yet now I've wireless thermostats and the app on everyones phone and potential Google Home control and historical temp logging etc.

Really the only reason why I care at all if all day thermostat controlled temp is saving us or costing us money is that other family members are worrying about the cost of having the 'heating on all day' and are sceptical of my claims that its actually literally hardly ever on in reality. I want to show them numbers to stop them worrying.

Thanks again Cerco.