Is pressurised hot water worth it, with oil?

[LarryS.]

Non woodworking question but hoping someone here has experience

we have an oil boiler and hot water tank, but would “like” pressurised hot water for

filing the bath
Showers
Filling the paddling pool for the 3 little ones

We’re considering switching to a non vented system, however the costs are about 2 grand, and there seems to be a couple of drawbacks
1. We’d need to take up a valuable space in the utility room for a bigger tank (current one is under a sloping dorma roof)
2. We’d spend more on oil to heat it more often on the off chance we’d need it for the showers (current shower is electric)
In the past in gas supply areas I had a Combi boiler which was fantastic, but when we moved here our plumber said oil Combis were too unreliable

so right now I’m thinking we stick with what we’ve got, but does anyone have any experience of pressurising a system, oil Combis ? That could offer some insight ?

thanks

Paul

 

[sunnybob]

Talk to the local experts. Its not uncommon for a tradesman to rubbish a product just because he doesnt want the hassle of working out how to use it properly.
https://www.flexiheatuk.com/oil-combi-boilers/

 

[adidat]

I'm looking at having a calor tank put in then getting a gas combi.

Adidat

 

[AJB Temple]

We have an ancient oil boiler, about to be replaced with a more efficient one. When we moved here the first thing we did was fit a Megalflow pressurised hot water sealed system to replace the loft fed vented cold tank etc.

It is MUCH better. Proper shower pressures in the bathrooms etc.

 

[Spectric]

Hi there

You will find that a sealed system with a system boiler and hotwater cylinder are more efficient than a combi boiler because the system boiler heats the water over a period of time, my one takes 35 minutes from cold wheras the combi has to use large volumes of gas to produce instant hot water. You will get a much better shower as well because you have the stored water capacity in the cylinder. I personaly believe that although overall the system is slightly more complicated it is a better system because you do not have the complexity of the combi boiler and often the cost of OEM boiler parts. You have to remember that the installer needs to be G3 registered as well.

 

[Doug71]

I have an oil boiler and sealed system which works really well. Regarding the running costs for heating water I'm amazed how little oil it uses, the level in the oil tank hardly seems to move in the months that the heating is not on.

You fill the paddling pool with hot water? Maybe I'm a bad dad or maybe it's because I'm from Yorkshire but I just use the garden hose!

 

[MikeG.]

The heat source is irrelevant. As always, it is just hot water circulating in a tank within a coil heat exchanger, so where that heat comes from makes no difference. Is a sealed system superior to a vented one with header tanks? In my view, yes, by a country mile.

 

[stuartpaul]

We have an oil fired combi and we're generally very happy with it. My only minor moan is it doesn't give me the flow rate I'd like for the shower, - but on the other hand the wife thinks it's fine (so really it's fine then!). In six months of hot water only we've used just over 65 litres of oil according to the gauge (I thought it was broken because it wasn't moving!).

The unreliability comment does sound a bit 'off' and as Bob says, just a tradesman who doesn't want the job? Our Worcester is fine with no reliability issues at all.

 

[Rorschach]

How often do you take a bath? Are you happy with the current electric shower?

This could work out to be very expensive for very little gain, sometimes you need to have a good think about the practicalities and cost/benefit.

Of course if you need a new boiler anyway, that would change things a lot.

Just a sample case. My sister had her bathroom replaced not too long ago and switched from an electric shower to a boiler fed shower, this involved quite a bit of work as new pipes had to be run as well the cost of the new system etc. She was happy to do it thought because she was unhappy with the electric shower.
A few weeks ago she had cause to shower at our house (electric shower) and she said it was fantastic and almost as good as her new boiler fed shower. Turns out she could have spent approx £100 replacing the shower and saved money while still getting the benefits of an electric shower.

 

[flying haggis]

I'm looking at having a calor tank put in then getting a gas combi.

Adidat

you got deep pockets then, calor is a very expensive way to heat a house

 

[AES]

Re showers, I guess that electric ones vary, but I must say I've never been very positively impressed, and mostly very UNimpressed (hotels, mostly old house renovations, etc. Charming and all that, but not if the shower doesn't work well when everyone else in the hotel is having a shower at roughly the same time in the morning).

Here (Switzerland) pressurised systems are more of less standard and in our case, unless we run 2 showers full bore together (one's down near the cellar, only a couple of metres pipe run from the CH, the other's right upstairs at least a 20 metre pipe run) then our system is always excellent, with always plenty of hot water and pressure in either CH mode (Winter heating and hot water, summer, hot water only).

When we lived in rented flats too (one with 12 flats in it, the other with 5) these both had pressurised systems and never had anything but excellent, hot, long-lasting showers.

The only drawback that we have in particular here (like many smaller villages some way out of town here) is that there's no piped gas. That means bottled gas (horrendously expensive, as someone's already said); electricity (also expensive here, despite the abundance of hydro-electric - "Governments will be Governments" and all that!!!!); subterranean heat pump (pretty good apparently, but at age 75 I doubt we'll recover the initial very high boring/installation costs in our lifetime); wood (never tried, but next door's pellets burner stinks and smokes quite a bit at start up); or "the arch enemy", oil.

Oil is what we have now, has always been here (we moved to this house in 1993, and the house was built in the mid 1960's), and most of our village seems to be oil too - at least the older houses anyway.

BUT in their latest "environmental regs", our "Governments will be Governments" have said that from now on the "energy surcharge" on oil will go up to roughly 200 quid extra on top of every 1,000 litres we buy (our tank is 5,500 litres and lasts about 2 normal years if we run it to empty - which we don't). AND after 2026 it will be forbidden to buy new oil heating systems any more.

As I had our system put in in 1997 (replacing the one put in at new build) I reckon that sooner or later, we're going to need new. But at age 75 and in view of the above new regs, I think I'll leave that to someone else to sort out!

So at least one advantage of being an old fogey then!


But back to showers, ours work very well indeed. But I THINK that's due to the pressurised system, not to the method of heating the water.

HTH

 

[Oddbod70]

As ajb and spectric, pressurised cylinder and standard (or system) oil boiler. I‘m pretty sure some megaflows (and similar alternatives) come with secondary coils for other heat sources, eg electric, solar, wood etc. Unfortunately i can see the day when electric or biomass are the only options we have, and if that happens relying on a combi for HW might not be so great.
.

 

[Lons]

Hi Paul
If your boiler and system are working well and don't need replacing for other reasons then maybe a pressure pump will work for you, there are a number of options available at far lower cost than system replacement and emit nothing like the intrusive noise of a power shower pump. We have one of the latter powering 2 showers, effective but noisy whereas a whole house pump is more of a background hum depending where it's sited.
Worth at least considering, plenty of info on the internet.

We have a similar system, oil boiler, vented system and works well, no way would I personally consider a Combi as I've seen first hand too many expensive premature failures however while our hot water to taps is ok it's not great at some of the taps and I bought a basic whole house pump years ago - just never got around to fitting it so it's sitting on a shelf in the garage. Grundig I think but would need to look to be certain.

EDIT: GRUNDFOS. Grundig made TVs

 

[LarryS.]

Thanks everyone for the input, I’m going to do some digging on the whole house pumps as the boiler is only 5 years old and the rest of the system works fine, apart from the pressure

whar a great resource this forum continues to be

 

[Roseland 2]

I've twice lived in properties with Combi boilers, and I think they are dreadful; there is a tradeoff between flow rate and temperature. I've also used pumped showers which are "adequate" but often noisy. I replaced a conventional header tank/cylinder with a pressurised system (Megaflow) and it is one of the best investments I've made. Plenty of high pressure hot water, with little pressure difference between hot and cold, so thermostatic valves work well.

Andrew

 

[Geoff_S]

We had combis for years which were great until more than one outlet was turned on. For example, I would be having a shower, my wife would decide to run a bath, or the washing machine would be turned on, and I then got a cold shower. The problem was not so much the boiler, it was 40KW, it was the water pressure.

So when we had some major work done we replaced the boiler with a "normal" boiler and installed a hot water storage tank. However, at the water entry point to the house we installed a Grundfos Home Booster 4.5 Bar. All pressure problems solved.

You're not allowed to pump water direct from the main, so what this does is it has a 180ltr storage tank that fills up at normal pressure and it is then that water tank that is pumped at 4.5 bar.

We did consider a Megaflow but were told that it does not pump the cold water, just the hot. And it only pumps at the supplied mains pressure, which would have been no good to us.

Mind you, when we put the garden sprinkler on, we have to now be careful not to be watering next door's garden as well!

 

[Andy F]

We just (last week) swapped out an old oil fired Megaflow system for a new Worcester combi. The flow rate is the same, the heat is the same (or slightly better) and the radiators are now so hot we can smell the paint melting on them.

I would have liked to keep the megaflow, but it was 20 years old and the heat source was a very inefficient Esse range cooker which had once been converted from coal, drank oil like I drink Rioja ( a lot) and took up too much space in the kitchen. There are only two of us though, so as long as we can shower and keep warm, there isnt too much demand on the system.

Andy

 

[clogs]

depending where you are using solar to get the water temp up in the feeder tank will save lots of money but it'll be an expensive system to add on.....
but no system is perfect.....
and I beleive in the UK gas Boilers will be outlawed in the near future......?
dread to think what the price of elec will be then........
Luckily we use solar and a wood boiler with a 300liter hot water tank....cheap as chips...

 

[Nigel Burden]

We have solar panels, and most of our hot water in the Spring, Summer and Autumn is supplied by solar, our boiler only really being used in the winter. In Winter we will get hot water on a bright day.

Nigel.

 

[AJB Temple]

depending where you are using solar to get the water temp up in the feeder tank will save lots of money but it'll be an expensive system to add on.....
but no system is perfect.....
and I beleive in the UK gas Boilers will be outlawed in the near future......?
dread to think what the price of elec will be then........
Luckily we use solar and a wood boiler with a 300liter hot water tank....cheap as chips...

It is not true that gas boilers are being banned! This applies only to new homes from 2025. A drop in the ocean