Hot Water Tank.. what size ????

gooseygander

Hi all, new build 2800sq foot house with air to water heating system. Spec by plumber and heating guys is for a 260ltr hot water tank which will be located in garage. We are a family of 5. Is this big enough ? Should I be going for 300ltr tank ??? Will this cost much more to heat ???, also heating guys told us that we will have no need for immersion or electric shower in the house due to having a constant supply of hot water from the heat pump, any opinions on this ??. House will have 3 showers and two large baths, thanks in advance for all opinions

Calahonda52

Tank in garage = Longer pipe runs= wasted water and energy
100% reliance on air to water pump with no back up is stupid.
Dont know any A to W heat pump that will do>= 60 degree water all year unaided.
Tank size is a fn of ability of tank to gain heat and water demand.
You won't always have 5

gooseygander

Calahonda52 wrote: »

Tank in garage = Longer pipe runs= wasted water and energy
100% reliance on air to water pump with no back up is stupid.
Dont know any A to W heat pump that will do>= 60 degree water all year unaided.
Tank size is a fn of ability of tank to gain heat and water demand.
You won't always have 5

Thanks calahonda, sorry but hot water tank is not in garage as I stated but will be in house, what back up would you suggest ?, sorry but don't understand your point on tank size (fn of ability ??), and your last point is very true even though it makes me very sad at the thought of it as I suppose my babies/children will grow up too fast. Thanks for your input

Calahonda52

Have u gas or oil or is the whole thing based on the A to W pump?

Fn is short for function.
My gas boiler heats a high gain 300 l tank I have in 11 minutes, 25kW boiler, the tank is nearly all coil.
Whsts thr make spec of HP.

Calahonda52

Have u gas or oil or is the whole thing based on the A to W pump?

Fn is short for function.
My gas boiler heats a high gain 300 l tank I have in 11 minutes, 25kW boiler, the tank is nearly all coil.
What's the make spec of HP.?

gooseygander

Calahonda52 wrote: »

Have u gas or oil or is the whole thing based on the A to W pump?

Fn is short for function.
My gas boiler heats a high gain 300 l tank I have in 11 minutes, 25kW boiler, the tank is nearly all coil.
What's the make spec of HP.?

No gas, no oil. House will be heated by Daikin 14kw heatpump. We will also have two wood burning stoves installed but they won't be connected to a back boiler. House will have high degree of air tightness and stoves will have external air supply. H pump will be sole supplier of hot water. Do you reckon I am making an error ?

agusta

My brother has an air to water heat from from this company http://www.ashgrove.ie/products/air-to-water-heat-pumps/

These units have a immersion heater in them to help the HP at times when it is not able to heat sufficient hot water,like in extreme weather conditions.This is the back up.
House is 2,600 sqft,water tank in utility
Hot water all year round,never short,3 people in house
I dont know what kw it is
Running cost last year,under a 1000 euro last year

They also have a two sided stove,Its only on a few times during the year,more for show than heat.They dont have a heat requirement from the stove

Calahonda52

Useful info Maximus Agusta!, thank u.
What follows is food for thought.

Hot water will never be short as the immersion will pick up the slack.
Do the unit have 2 elec usage meters, one for HP and one for immersion?

(Folk talk about unlimited hot water bla bla..
But what is the actual demand?
Do they bath every day?
Do they have long, pumped, body jet shower?
Worse, are there teenagers?
Does clothes washer use HW.
Dishwasher? )

This is an issue for most dual or treble heating systems, the elec picks up the slack and the punter dont know what the real contribution from the capital cost expensive Renewables.

What is annual servicing fee, more than for a boiler as it is an industrial fridge?
What was the installed capital cost? Maybe 20/25/30 k?
Whats the life of the unit?
Thats a lot of shekels.

I dont have any issue with any of this as long as the lifetime cost calcs are done for alternative solutions.
In most domestic cases they are not.
Keep well.

gooseygander

Capital costs for a new build for air to water system with under floor up and downstairs came in more or less at same costing for condenser oil boiler with radiators and solar heated water, all down to personal choice, no right or wrong answer in this case, what might work for me and my family might not suit another, best of luck

Calahonda52

Calahonda52

Have a look at the post in the RE Section under C&P about GSHP ¥ ASHP.
I cant post links