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(20 Posts)
Cherrypickerpopoff Sun 17-Mar-19 09:30:08

Morning, hope you don't mind me posting for traffic.

We've recently moved from a house with a combi boiler, instant hot water and a trad wall-mounted thermostat which automatically warmed the house if it dropped below 17.

This house has an unvented hot water cylinder and NEST thermostat. Our energy bills have DOUBLED. It's a brand new system.

Do any of you use a Nest system and can you advise me on the best way to set it, please?

The hot water is the biggest concern as we have it on 3am til 11pm (we're a big family and need hot water all day due to sports etc). We thought it would be more cost effective to keep the water on all day than have to keep reheating 500l of water from cold. Plus, if you want a quick shower, there's no hot water 'on tap' if the water is off. (1st World problems, I know). I need to work out a way to reduce costs and energy consumption.

Also, as the NEST uses the WiFi, what happens at night when the WiFi goes off??!!!

Thanks!

lockelamora Sun 17-Mar-19 09:54:02

Don't know anything about about Nest, but a few things about unvented hot water cylinders...

You definitely don't need it on for 20 hours a day - we have our hot water on for one hour a day which is enough for us (two adults). Why not try having it on for a couple of hours in the morning and again in the afternoon? If that's still fine, reduce it some more. The cylinder is really well insulated so only loses a few degrees a day, even without being heated again.

Also, you probably have an immersion heater in the hot water cylinder, make sure that's switched off because it's much less efficient than your boiler.

Cherrypickerpopoff Sun 17-Mar-19 10:01:21

Thanks for your reply. I hate not understanding how these things work and I hate not having hot water lol. We are a big family so the water gets used a lot, especially weekends with sports being played. Im going to try having it on morning and evenings weekdays and hope it helps. What I'm worried about is if the water is used up by morning showers, it'll refill and stay cold all day (and thus no showers in day) and also cost a lot to reheat from scratch. I'll look for an emersion heater switch. Thanks for your help.

Shoppingwithmother Sun 17-Mar-19 10:09:32

As PP said, water stays hot in the tanks for ages. We had our boiler changed and were without one for a short period. We had showers in the electric shower so we didn’t use up th shot water in the tank and it was still hot enough to wash up/wash hands 3 days later!

The hot water tank won’t fill up with cold water when it’s used up and then need to be heated - the hot water in the tank comes from the boiler and is stored in the tank. If you run out of hot water or have used a lot, you should be able to just heat some more water by pressing the “advance” button or similar.

But yes, usually an hour in the morning is enough, but an additional hour in the afternoon should work for you.

Cherrypickerpopoff Sun 17-Mar-19 10:12:53

*immersion

Cherrypickerpopoff Sun 17-Mar-19 10:27:07

Thank you for your help. The info we've been given is minimal and I've been googling and googling but you've helped me more in 1/2 hour than all that googling.

So, to clarify, the water is heated BEFORE it goes into the cylinder and I assume is replaced as the hot water is drawn upon. Does the cylinder then heat it (using gas rather than electric immersion) (during the hours I ask it to) to keep it at a certain temperature? If that's the case, why would we need the immersion? Also doesn't explain that when the nest was accidentally put on eco mode, we had no hot water in the afternoon (2ish) after we'd all had showers first thing. I have a 'boost' button on the Nest but it doesn't seem to 'boost' as yiu still have to wait ages for hot water to come through.

DisplayPurposesOnly Sun 17-Mar-19 10:27:12

I really think you need an electric shower to have constant access to hot water as you describe.

circlemat Sun 17-Mar-19 10:44:46

We have a similar system but with HIVE and this is our hot water schedule. We always have plenty. The only thing I do is if I randomly use a lot of hot water in the middle of the day then I will boost the hot water for 30 minutes from the app and that is enough to warm the water up again for the rest of the day.

Our tank isn't filled with warm water from the boiler, it's filled from a cold water tank in the loft.

Also why does your WiFi go off at night?

As others have said an electric shower may be best for you.

Shoppingwithmother Sun 17-Mar-19 10:45:28

The cylinder can have an immersion heater in it which heats the water in the tank, but they are (or should be) heavily insulated with a “jacket” of insulation, which is what keeps the heat in.

A boost or advance to this kind of system won’t give you instant hot water, maybe it might take half an hour.

I agree, I think an electric shower would meet you needs as it provides unlimited instant hot water heated directly by the shower itself, not taking any from the hot water tank, and only heating the exact amount used at any time.

Gruffin Sun 17-Mar-19 10:48:44

We just keep ours on an hour each morning(family of five). I just add + 1hr afterwards if I know I need to use a lot of hot water later that day. Also teach the kids to limit their shower time to max 10 minutes.

LovingLola Sun 17-Mar-19 10:48:49

How long are people staying in the shower ? We used to limit showers to less than 5 minutes to ensure plenty of hot water in the mornings.
In fact I shower in about 2 minutes - ds and did could be there for 10!

dementedpixie Sun 17-Mar-19 10:55:23

We have hot water on for a couple of hours twice a day. We do have an electric shower that feeds from the cold water supply so doesn't use water from the hot water cylinder.

Inforthelonghaul Sun 17-Mar-19 11:31:10

We a mega flo cylinder with an ordinary boiler. The hot water is on for an hour in the morning and an hour in the evening and this is usually sufficient for an active family of five. If we need additional hot water we put the programmer on for an hour and within 20 mins can easily run a bath etc. The immersion heater should be switched off. It’s a brilliant thing to have for an emergency if the boiler stops working but otherwise not needed and will increase bills hugely if left on. Water should stay piping hot in the cylinder so really an hour or two a day should be ample.

Inforthelonghaul Sun 17-Mar-19 11:31:59

Don’t know anything about the Neet though, we just have a wall thermostat and programmer to switch stuff on and off.

Cherrypickerpopoff Sun 17-Mar-19 12:43:22

OK, so I found the immersion and it's off at the wall. Will give it a week with a couple of hours in the morning and in the evening (plus over lunchtime at the weekends). Wish I'd got a smart meter now so I can see if it changes the usage. There's no way we can afford double bills long-term.

For PP - we turn WiFi off over night so we don't fry our brains more than we need to. Plus the kids can't play on devices until it goes back on.

RE electric showers, I find you have to fun round the shower to get wet! The old combi boiler gave instant hot water without the need for an electric shower. We'll just have to get used to this new system and make it work for us. Thanks for your tips and insights.

circlemat Sun 17-Mar-19 12:48:04

Oh I see with the WiFi, my daughter is only 1 so not thought of that. Will probably be doing it in the future though 😂

PettyContractor Sun 17-Mar-19 13:07:52

With regard to Wifi, it might be worth looking if you can selectively set schedules for different devices on the router, so that you don't have to turn it off. With more and more dependence on wifi, the disadvantages of turning it off completely are probably only going to get worse.

Just as an example, my landline number doesn't work if the wifi is off, my Sky box and Smart TV won'd download software updates if not connected to internet overnight. If "wifi off" actually means the router is switched off, the router itself won't pick up software updates.

QuirkyQuark Sun 17-Mar-19 13:13:32

Honestly once you get used to heating just morning and evening you won't notice the difference. We only have it on for a couple hours f hours a day even when dd is home from uni and forgets that hot water here isn't included like it is in her shower in halls.

We're about to switch to a combi boiler and I'm terrified that my bills will increase confused

PettyContractor Sun 17-Mar-19 13:15:09

I have a traditional boiler and hot water tank setup. Once the water has been heated up, it stays warm for a couple of days, if not used. When the boiler was being changed, there was no boiler (or immersion heater) to heat up water, and we didn't run out of hot water. (Though we were being careful with how much we used.)

So I would just have the water on from half-an-hour before the first person gets up until bed-time. The size of the water heating bill will depend on how much hot water gets take out at the taps, not on your heating schedule. (Except to the extent the heating schedule stops hot water being available when it's wanted!)

PettyContractor Sun 17-Mar-19 13:24:18

Having said that I doubt you can cut hot water bills other than by using less hot water, are you sure it's the hot water that's the problem? Maybe the new house is less energy efficient and it's the heating that's the problem?

I take quarterly meter readings, so I can see what my gas usage is in summer, and consequently I can work out how much of my bill is home heating versus cooking and hot water. (Home heating is 75% of the annual gas bill, and I have well-insulated newish-build house.)

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