Tankless water heater?

cjmca

Hi,

I've heard that tankless water heaters are very popular in the US. I live in an apartment, and the water tank takes up a lot of space, which I'm short of. In addition, the water tank system is very noisy, and located near the 2 bedrooms. If flatmate has a shower, I wake up...

I don't know if a tankless water heater is the way to go, or even feasable? Any info/advice appreciated.

Thanks

heinbloed

What sort of energy supply is available? What is the flow rate of the water ?

cjmca

heinbloed wrote: »

What sort of energy supply is available? What is the flow rate of the water ?

Gas supply available. I don't know the flow rate of the water, how would I go about finding out?

Thanks

heinbloed

You could get a "continous-flow water heater" (geyser) running on gas. For these one has to have a minimum of a flow rate, to avoid over-heating.
Similar to an electric shower.

Gas heaters are usually cheaper to run but will take more space than an electric shower. They need an air supply and an outlet for the CO2, either a hole through the wall or connected to the chimney.
Electric water heater/shower modules can be installed virtually anywhere.
In the bath room, under the kitchen sink.
Depending on the demand (liters of hot water per minute) a standard 13 amp connection will be enough. But to fill a bath tub a 3 phase electricity connection would be necessary.

cjmca

heinbloed wrote: »

You could get a "continous-flow water heater" (geyser) running on gas. For these one has to have a minimum of a flow rate, to avoid over-heating.
Similar to an electric shower.

Gas heaters are usually cheaper to run but will take more space than an electric shower. They need an air supply and an outlet for the CO2, either a hole through the wall or connected to the chimney.
Electric water heater/shower modules can be installed virtually anywhere.
In the bath room, under the kitchen sink.
Depending on the demand (liters of hot water per minute) a standard 13 amp connection will be enough. But to fill a bath tub a 3 phase electricity connection would be necessary.

Thanks very much for the info. I was looking to get a unit that would cover all appliances throughout my apartment - i.e. instead of individual units under the sink, for the shower etc.

I'm not sure if there is a standalone unit that I'm able to obtain in Ireland. If there is, I'm not sure the current plumbing etc. in my apartment is compatible. If such a unit is available in Ireland, do you know of any suppliers/the cost? I'd also really need someone very knowledgeable to install it and have someone available to service it annually...

If it runs on gas, would this hike up my gas bill considerably?

Thanks again for the advice - I'm not very knowledgeable obviously!

sullzz

did you think about fitting a combi boiler instead of your existing boiler , keep in mind though there would be a bit of pipework involved , also this would only do away with your hot water cylinder and not your storage cistern

heinbloed

Well, as sullz said already, a combi-condensing boiler seems to be the straight forward solution.
If you have already a gas boiler installed then it would be easy to swap the the old boiler for a new combi condensing boiler.
As long as the water supply for the apartment is pressurised (as in modern buildings/apartment blocks) then the existing pipes can be used. A pressurised system is identified by the lack of a cistern, a feeder or hopper tank, in the attick.

The gas bill would actually be reduced, storage losses from the thermal storage tank being avoided.
All hot water outlets could be connected to this boiler.
Depending on the size of the plumbing system (meters of piping) and the number of users (liters of hot water to be drawn at the same moment) the size of the combi-boiler should be chosen.
A 1-person household would not draw more then 1 tap or 1 shower head at the same moment, so around 10 liters of hot water per minute is the demand. With water saving shower heads/taps this demand is even less, around 4-6 liters per minute. With these water saving devices even the smalest available boiler would cover a 2 person household with DHW easily.

For a standard household the smallest available combi-condensing boiler would be sufficient, 10-15 kW on the DHW side.

The power of a boiler is stated in kW. With a combi-condensing boiler there are two power statements on the boiler label, one for the domestic hot water outlet (DHW) and another one for the space heating circuit.



Talk to a plumber to have a look at the existing situation and to make a recommendation. Shop around and get more than one offer.

If you are living "in the North" there might be subsidies available for a combi-condensing boiler, about 2 or 3 years ago these where advertised by the gas body ("free-up space, throw out the cistern, the tank, heat for cheap" and the like). Sale, installation and dumping of the old equipment were organized by the gas body for a fixed sum.

Good luck!