Heat Pump – Heat Load Calculation & running costs. « Alternative Technology Assn Forums

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Heat Pump – Heat Load Calculation & running costs.

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Started 4 years ago by foxint
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foxint
Member

Hi Guys….

There is a similar post, but I do not want to highjack it. Hope you do not think this is stupid. I am looking to replace my gas boiler for my hydronic heating (panels) I live in middle of NSW and it gets cold. I am looking at Skyline Engineering (who are excellent), Tivok and Stiebel Eltron. I have the following problems:

1. One installer will not explain how he calculated the Heat Load. I tried to backwards calculate this on excel, but he did not even use my exact room calculations and he will not explain. Saying it is far to complex. His room volume calculation does not even match mine. So is there an excel spread sheet for head load calculations.
2. I know cost of the equipment – lots.
3. I know the cost of my electricity
4. I do NOT know the cost of heat pump running.
5. The installers will not give me a running cost for the unit(s). Saying there are far too many variables. But it will be cheaper than gas…. but how much….
6. Yes, there are variables, but if I cannot compare apples with apples, how can I compare the cost of gas and the cost of a heat pump. Plus, the wife is not as excited about this as much as I …good. But I need to know

Any help would be gratefully accepted. Thank you. The forum is great.

Posted Saturday 30 Dec 2017 @ 6:24:11 am from IP #
Benny
Member

Do you know from past records how much gas you were using - in winter - over and above what is used for cooking/hot water? If you can assume say 80% efficiency of gas boiler that should give you some idea of how much energy you need.

Irrespective of how much total energy you need, can you just compare per kWh/MJ ? ie what is gas cost per MJ and what is electricity cost divided by efficiency of heat pump.

Posted Saturday 30 Dec 2017 @ 7:39:40 am from IP #
foxint
Member

Hi Benny

Thank you for the reply.

Only heating and hot water. We heat the house for about 9-10 months of the year obviously the 2 months on each side are mild. But the boiler even went on 2 weeks ago for a short time. We keep the thermostat at 18C all year.

I used about 6,000 cu meters of Gas (heating) at a cost of AUD5,512.84. I removed the MJ calculation as I thought it was a flaky and dishonest calculation (I can put it back).

I am a bit thick…what is the calculation?

Dan

Posted Saturday 30 Dec 2017 @ 7:58:11 am from IP #
Ben1
Member

Your bills should show how many MJ per cubic metre of gas. It varies a bit quarter to quarter but should be in the range of 35-37 MJ/m3 = 210 GJ. Crikey that is a lot of gas! Have you thought about increasing your insulation levels and upgrading your windows?

Posted Saturday 30 Dec 2017 @ 11:52:55 pm from IP #
foxint
Member

Hi Benny

Thank you for the reply.

I have all the data:
Oct-Jan 16,701 MJ Total Cost 439.75 (5.44/day – basically Hot Water)
Jan-April 59,045 MJ Total Cost 1,366.51 (16.16/day)
April – July 85,268MJ Total Cost 1,374.45 (16.99/day)
Jul – Oct 92,914 MJ Total Cost 2,340.13 (27.98/day)
Total 226,929

I have 49 windows in the house and the are all single glazed and aluminium – so no thermal break and no insulation. When we did the renovation 4 years ago I “told” the builders to stuff as much insulation into the walls as possible….but they looked at me as if I was the devil. Not being on site 24/7 I can only “hope”….

You can see that there are 3 Quarters where the hydronic heating is on and 1 quarter when it is not.

Are you also saying that if I divide the MJ x 3.6 that will give me the kW power and this can be related to the cost of say a heat pump. So that means, in July – Oct it is 25,809.44 kW (or 280.53 kW a day – 92 days in the quarter). At my cost of electricity of 38cents (about) a heat pump will cost $106.60 per day

I am obvious getting something wrong??? I am getting really depressed
Dan

Posted Sunday 31 Dec 2017 @ 12:25:14 am from IP #
Benny
Member

Yes you convert MJ to kWh (not kW) by dividing by 3.6. So Jul-Oct you used 93,000 - 16000(HW) = 77000MJ = 21000kWh . Over 90 days thats 238kWh per day !!! ITS HUGE !!! Are you sure there's not a decimal point in there somewhere ? The highest I've ever seen a house use (in Perth for air con not heating) is 90kWh per day - 10kW AC on all day set at 18C. Whole primary schools use 300-400kWh per day.

If you need 238kWh of heat per day, then using a very efficient heat pump at say 4:1 , you'll use 60kWh of electricity per day - at 38c/kWh that would be $22 per day - who pays 38c/unit ?? Thats like a peak period business charge here in Perth.

Even your water use is extreme, 16000MJ is 4444kWh which over 90days is 49kWh per day. Most families with gas storage hot water use 10-15kWh per day. Do you have a recirculating hot water system ?

Posted Sunday 31 Dec 2017 @ 3:08:10 am from IP #
foxint
Member

See why I am depressed….

We are on time of use electricity. 7am – 10pm 38cents and over night 18cents. We are in Orange central west of NSW. Beautiful the day you arrive, hideously expensive forever.

I have checked the gas bill…. 2,500 (units used cu metres) x Heating Value (37.87) x Pressure Value (0.98140) = 92,914.05…I have it on excel and the $ match the Energy Australia bill….

Confused: If I use (same quarter) 92,914 MJ this is total use over 92 days and 24 hours a day and not all evenly used. That is about 1,000 MJ a day (1,009.93MJ) How can MJ be converted into kW/h…it surely can only be converted into total energy of kW???

If it is it kW…. 92,914MJ divided by 3.6 = 23,824.10 kW. Each day (92-day period) = 258.96 kW a day. If the heat pump is 4:1 then the total kW the machine uses is 64.73 kW each day. Assuming 24hrs that is 2.697 kW/h @ 38cents a kW/h = $1.025/hr or $24.60/day or (92-day quarter) is 2,263.28 or about the same as the gas – ($2,340.13)

Are my calculations wrong?

Posted Sunday 31 Dec 2017 @ 4:15:15 am from IP #
Ben1
Member

3.6 MJ per kWh. So yes, 92,914 MJ = 25,809 kWh for a quarter or 280 kWh/day. That is out of control. Almost any energy efficiency measure you implement will have a very fast payback.

Posted Sunday 31 Dec 2017 @ 12:08:06 pm from IP #
Bushwalker
Member

"Assuming 24hrs that is 2.697 kW/h @ 38cents a kW/h = $1.025/hr or $24.60/day or (92-day quarter) is 2,263.28 or about the same as the gas – ($2,340.13)

Are my calculations wrong?"

Only because 9 hours are 18c/kWh and daily is 38c/kWh

Replace gas with more efficient heat pumps, move insulation up: double glazed and insulated frames, Check and repair any air leaks throughout the house.

How big is the block?

Posted Sunday 31 Dec 2017 @ 2:12:26 pm from IP #
foxint
Member

Happy New Year. Thank you for all your comments. They are great.

Thanks for confirming my mathematics.

I am using 38 cents a kW/h as this is the worst case. We are a high use house (about 34kW a day). Since it is not practical to use the 18-cent power.

My conclusion is the heat pump is not much cheaper to run than the gas NOW, plus to install a heat pump system to the house is about 30K. Payback is a long time…I think doing the numbers was beneficial, but rushing into heat pump technology now is not economic.

Agreed other things need to be done. When we did the renovations (4-years ago) I told the builders to put as much insulation in the walls as possible. We have insulation in the roof….so I am left with the expensive things.

But with a 475-sq. meter home and 49 shi* windows, I would have to be rich and I am not….

Any comments/suggestions most welcome

Posted Monday 1 Jan 2018 @ 1:52:55 am from IP #
Bushwalker
Member

Ok. So the house has a temperature problem.

Ideas:

Section the living area away from bedroom and utilities of laundry and bathrooms etc. Run the heating in the living area at the normal temp. Switch to bedrooms just before sleep time.

Use a timer to turn off the heating when members are away from the house.

Replace the worst windows in the living areas, add plastic insulation to cover the other areas (you can just use plastic film with a gap between the plastic and the glass or better the aluminium frames)

Find an area of the roof or garage to add solar to run a grid independant heatpump heating system.

Find a tech to test the air leakage of the house. They put a fan system into a door and will be able to measure the air leakage of the hose and identify the worst areas that can be improved.

Use an IR scanner to identify heat leaks through the walls. If major leaks are identified, start planning to repair them.

Use a heatpump hot water system running overnight at 18c/kWh to store heat and run hot water radiators in the living area during the day.

Look for a more reasonable efficient house and swap house (buy/sell)

Probably more ideas, but seems to be many options.

Posted Monday 1 Jan 2018 @ 3:15:46 am from IP #
foxint
Member

Bushwalker – Thank you.

1. Section the living area away from bedroom and utilities of laundry and bathrooms etc.
a. House is already split in 2
b. Part A has the bedrooms and laundry
c. Part B has kitchen, living, dinning, guest bedroom and office
2. Run the heating in the living area at the normal temp. Switch to bedrooms just before sleep time.
a. I have 2 separate distinct heating systems 1 for Part A and 1 for Part B
b. Have 2 thermostats one for each. We set them (at what I have been told is low) at 18C
3. Use a timer to turn off the heating when members are away from the house.
a. I work from home and never leave
b. Trapped…like a B-grade movie
4. Replace the worst windows in the living areas, add plastic insulation to cover the other areas (you can just use plastic film with a gap between the plastic and the glass or better the aluminium frames)
a. Great idea. I have 49 windows from normal size to Huge…
b. On my list of many things. But living expenses such as GAS, health insurance and school fees tend to get in the way.
5. Find an area of the roof or garage to add solar to run a grid independent heat pump heating system.
a. I have PV and batteries and use more than I produce and not much roof space left
b. I will have to remove the pool heater to liberate more roof space
c. But I will be hitting the max capacity of the Inverter (8.3 kW of PV and 10 kW inverter
d. Will be hitting max capacity of local and state legislation – will have to check. If you know about NSW I would like to know
e. $30K for a heat pump to heat the house is a little (lot) more than the wife is willing to allow me to borrow. I do not have that amount of money burning a hole in my pocket.
6. Find a tech to test the air leakage of the house. They put a fan system into a door and will be able to measure the air leakage of the hose and identify the worst areas that can be improved.
a. Great idea
7. Use an IR scanner to identify heat leaks through the walls. If major leaks are identified, start planning to repair them.
a. Great Idea
8. Use a heat pump hot water system running overnight at 18c/kWh to store heat
a. Great idea – possibly the only one I could get past the wife (but she is not keen)
b. BUT…. I doubt the heat pump will run overnight in Orange, especially in winter. So, therefore I plugged in 38cents a kW/hour. As I doubt the heat pump will draw much heat overnight. So, it remains about the same cost as the GAS without the capital outlay.
9. Run hot water radiators in the living area during the day.
a. I am a little confused with this suggestion???
10. Look for a more reasonable efficient house and swap house (buy/sell) Probably more ideas, but seems to be many options.
a. Good idea. But the wife likes the house, so do I. It is unlikely I will find another house with the level of accommodation in the same location. Plus, we renovated 4 years ago and still have work. We will not get what we outlaid. It is in the country and we did suffer (unlike Sydney) a housing price drop when Newcrest mining retrenched staff. So not happening.

Thanks for the great suggestions, but I think I have a tough problem.

Posted Monday 1 Jan 2018 @ 3:36:53 am from IP #
Bushwalker
Member

Orange NSW? https://www.yr.no/place/Australia/New_South_Wales/Orange/statistics.html

Minimum temps above zero. Heatpump compressor will work fine, especially if you require a suitable unit in the cooler weather time. You can run one in the snow if the spec is correct.

9. Run hot water radiators in the living area during the day.

The hot water radiators would run for the storage water from number 8, heat pump hot water system.

Do you have significant winter sun on your windows?

Is your land small or large? With space, you could add solar panels on a frame.

If you have PV and batteries, what do they run?

Posted Monday 1 Jan 2018 @ 3:56:38 am from IP #
foxint
Member

Bushwalker

Thanks again. You sure know your stuff.

OK…run the hydronic heating in the living areas during the day….and turn off the sleeping area. I must install my new thermostats (Honeywell CM907), that may allow more flexibility – Christmas present to myself….

I am talking with Sanden, Tivok and Stieble Eltron about hot water. They (the re-sellers) are not that sure about Orange. If it can run overnight that is OK…. but I am sure I have seen minus -C temperatures. But the link says not. So that takes my (most expensive heat pump hot water) to $2.20 per day vs the gas of 4.39 per day – not accurate as the dryer is gas, but if we assume only 25% is the dryer, this is still make the hot water on gas $3.29…So yes, the hot water heat pump is making more sense…. not forgetting the capital costs and installation.

Any suggestions for the hot water? I have 3 daughters a wife and I….

Do I have significant winter sun on my windows???? I think so, not sure what you are asking. House faces north.

We have 2,000 sq. m. But as I said I am hitting my head at the government ceilings plus my inverter is only 10kW.

The PV (32 panels @ 0.26 kW max 8.32 kW) and the batteries (Sonnen 8 kW) run the house…. everything aside from heating and hot water. Yes, we/I use a lot of power. I just added 2kW of batteries 2 weeks ago to take the battery to 10kW…. we will see the results. In winter I use far more than I produce and in summer (now) we will have to see.

Thanks

Posted Monday 1 Jan 2018 @ 4:20:58 am from IP #
Bushwalker
Member

Ok, the link was just the first I found. This one looks to have better statistics:

http://www.weatherzone.com.au/climate/station.jsp?lt=site&lc=63254

And BOM data: http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_display_type=dataDGraph&p_stn_num=063254&p_nccObsCode=123&p_month=13&p_startYear=2017

The average temps are above zero, but lowest go below zero.

Best to find out the details from the hot water crew.

Hot water, we use a Siddons separate heatpump system, the tank is inside, the compressor unit is outside. Has been in for years, and replaced an electric resistance unit, runs overnight on low power price. 320L. We replaced the shower heads with the Methven low water flow (can get them from the ATA) never runs out of hot water (320L) but only 4 ppl and no daughters...

Of course, an offgrid PV battery system could run a hot water system anytime...

Sun on the windows if not shaded, will deliver free heat during the day.

I'm in SA. We can add an independant PV system not connected to the grid. So a separate system could be used for heating etc without drawing from the grid. It's on our plan, and we already have a grid connected PV system with no battery system. Best to check if that is ok for NSW.

Dryer? We have one, run it maybe once or twice a month during winter. We just hang up the washed clothes etc on a washing line under the verandah and cops the midday and afternoon sun. If they are still moist, we have a clothes rack that gets them dried inside the house...

Since the energy pricing has been climbing the wall, we have been improving the house efficiency. Insulation, double glazing, sealing, etc, etc. We are in the Adelaide Hills so cooler than Adelaide but probably not as cold as Orange.

Posted Monday 1 Jan 2018 @ 4:51:22 am from IP #
arttt
Member

foxint said:

But with a 475-sq. meter home

You dont want to hear this but ...
475m house for 5 people is excessive. The excessive bills, the excessive cost of making it more efficient etc etc all stem from this. Generally people with very large houses have incomes to match so that they can live with the high costs without much pain.

If the bills are painful now they will get worse... then the maintenance will also be painful down the track.

In my opinion short of an income boost you should be thinking of an exit strategy.

Or.... divide it in 2 or 3 and rent half out. Make money and halve bills at the same time.

Posted Monday 1 Jan 2018 @ 8:47:31 am from IP #
foxint
Member

Hi Bushman

Thanks for the link to the weather.

We have record lows of Jan 1.1 Feb 1.3 Mar (0.1) Apr (4.6) May (6.6) June (8.3) Jul (7.7) Aug (6.2), Sep (5.4) Oct (3.0) Nov (1.7) and Dec 0.00

Averages are a warmer Jan 12.7 Feb 12.6 Mar 9.8 Apr 5.6 May 2.5 June 1.4 Aug 0.9 Sep 3.3 Oct 5.5 Nov 8.4 and Dec 10.4

Strange weather.

Thanks for the tip on Siddons

Hi Artt:

Yes, mate I am going to ignore your comments. Not in the generous spirit of the forum and certainly not charitable at this time of year. I would prefer if you refrained from further negative comments.

Thanks for all positive suggestions. I am taking them all on board. Of course, I must take things one at a time

Posted Monday 1 Jan 2018 @ 9:06:00 am from IP #
scott drew
Member

Hi Foxint,

Some other questions for you.

Of your 49 windows, how many have curtains with pelmets and or blinds that seal well?

If you have no curtains you will be losing a lot of heat in/out the windows. Curtains with pelmets or thick blinds that seal the window will reduce heat loss gain.

How much thermal mass do you have in the house? Thermal mass is bricks or masonry. The bricks warm up and hold the heat. I'm wondering what your walls are made of, both internal (between rooms) and external (between room and outside).

If you don't have much thermal mass there is no where for the heat to soak into, it'll seep out of the house to outside. The windows above will be a path that the heat can seep out.

Scott

Posted Monday 1 Jan 2018 @ 10:56:14 am from IP #
foxint
Member

Hi Scott

Thank you. I am sorry I got a little upset with Artt…. But good questions and points.

1. Curtains on all but 6 windows. On the list, but things like school fees get in the way.
a. Recently we install pelmets above all the windows (aside from those set into the walls) at a lot of expense. So, we are moving in the right direction – I think
b. We have plans to replace all the curtains with “better” ones
c. Any suggestions on type: traditional; blinds…?
d. 49 windows and some are floor to ceiling, it is an expensive task
2. Thermal mass
a. It is brick veneer with insulation in the walls and the ceiling. It will never get top marks (if any) for good thermal mass
b. Aside from bulldozing and rebuilding…???

Sorry for the questions. I was just throwing it out to you guys who are far more expert than I. Living in Orange is not the most “temperate” climate.

Dan

Posted Monday 1 Jan 2018 @ 8:10:37 pm from IP #
dave lawrence
Member

Hi Dan ,
it is understandable that you got a little upset with Artt ,but he was giving his honest opinion, and i tend to agree with him . It sounds like a huge ask what you are trying to do. Unfortunately most houses in Australia simply are not designed or built to be energy efficient ,and trying to retrofit them (especially in a harsh climate as you are in ) is a huge ask .
The windows will most likely be the largest source of heat loss/gain , and the cost of upgrading them will be huge .
Might I suggest, and I am aware you probably don't want to hear this ,is selecting a small part of the house, and somehow isolating that (thermally ) and concentrate of improving that portion of the house . Then if you get the results you are happy with maybe apply them to the remainder of the house .
I would also concentrate on appropriate shading/ insulating devices OUTSIDE the windows .
I hope your pelmets help ,they should... if correctly designed.
You could also apply pelmets to the inset windows.

Posted Monday 1 Jan 2018 @ 10:36:59 pm from IP #
foxint
Member

Hi Dave

Thank you for understanding. We must work with what we have and while I may (now) understand Artt’s comments, they were not helpful.

As I read one day, a Swedish architect suggested that the average Australia house has less thermal efficiency of a cardboard box with no lid.

The pelmets cost a fortune as they are now built into the wall and go to the ceiling, then the cornice have been applied. So, they look like they have been there forever.

I like to plan, and I like to have facts to back up my decisions. So far, the heat pump re-sellers could only tell me “it will be cheaper” and use the scare tactic about GAS. I agree, but being OCD I need the numbers.

Agree: the windows and the total fabric of the house suck. But (as reasonable blokes understand) having a family, moving is not an option.

In the collective expertise of the forum….” what are the best forms of window insulation?” It needs to have a good spouse approval rating. I know it I sick a piece of polystyrene on the windows this will work…. but not in the real world.

We close off 2 rooms that face south. Yes, they are cold. I have a thermometer in the South side bathroom and I have seen 3C. So not a pleasant place to relieve oneself…I do have some level of humour if treated with some respect.

Thank you for your well-crafted and considered comment.

Dan

Posted Monday 1 Jan 2018 @ 11:06:01 pm from IP #
dave lawrence
Member

depending on when the house was built, it probably does not have wall insulation either .
There are varying opinions on this website of how to retrofit insulation into cavity walls .
I know many people favour pumping foam into the cavity. I don't like that approach myself , but as you are finding out ,there are a million experts with a million contrary opinions .
I admire your willingness to do yuor own research and not accept the first salesmans spiel .

Posted Tuesday 2 Jan 2018 @ 1:06:04 am from IP #
foxint
Member

Hi Dave

You are correct about most houses – built to a price not a standard.

We guttered 50% of the house (built mid 1980’s) 4 years ago and I told the builder to stuff the walls with insulation. The only (one of the many) problem was we were in Melbourne (for my Mums funeral) when the windows were being done – well they were not done and where done, done badly. I am stuck.

The other 50% (sleeping) is 1994 built and who knows – too young and not bad enough to gut, so we are stuck.

What most people fail to realise with country living: houses are cheap…. but everything else is expensive. Electricity, Gas, Council Rates, food, petrol, PC stuff…everything. I buy in most things and cannot afford to buy local. Worst example: pool chlorinator same brand same model, in Orange $2,300 (not installed and I had to drive to the shop to get it), but delivered in the post from Sydney $945. If anyone can take anything from our conversation is avoid the bush unless you are rich or unwilling to adapt…. once you are here, you can never afford to buy in a capital city again.

No bad feeling, but as a realist, I need to investigate all the options. As I have written, I have installed PV then Batteries, fixed the old part of the house from mould and rotten floors, put in the pelmets. The local paper did a piece on my house and it would appear (according to the journo), I was the only one with batteries, certainly I have the largest domestic PV and I know the only Sonnen batteries in the town).

Now just asking for some “helpful” advice from those who may have trodden this road. There is no point in re-inventing the wheel….

Everyone has been brilliant. The world is full of sly salesmen and the government lies. So, it needs to come to good me like you to lead us out of the darkness.
D

Posted Tuesday 2 Jan 2018 @ 1:31:22 am from IP #
dave lawrence
Member

asking a disinterested builder to stuff insulation into the walls (as a retrofit )is almost certainly a waste of money as you have found out .
Why ?
because unless it is done with precision ,care and thoroughly (all of which take time, knowledge and patience) then the resluts will be far less than optimal .
An analogy I have often used is a bucket.
Imagine if you want it to hold water.
the house is the bucket ,the water is the heat .
Now imagine a few tiny holes in the bucket .
it is EXTREMELTY DIFFICULT to RETROSPECTIVELY insulate a cavity wall with bulk insulation., UNLESS you remove the internal lining and start again , OR you pump in expanding foam (thereby adversly affecting the cavity ...which is there for a reason.
BUT , as others have (perhaps less diplomatically ) pointed out on this thread, IT IS STILL WORTHWHILE trying to improve the thermal efficiency of the building envelope before ADHOC bandaids .thats my 2 cents worth .

Posted Tuesday 2 Jan 2018 @ 1:54:21 am from IP #
foxint
Member

Hi Dave,

All good comments. Again thank you.

But I did it in all good faith.

All the gyprock was removed, and we did start with the timbers and the brick. So not sure what else one can do, aside from DIY and start again. 50% of the house (old part) was guttered. We rebuilt, floors, walls, new kitchen 2 new bathrooms…. lots of work…. I am sure you have heard it all before….

In hindsight I should have bulldozed. But hindsight is perfect.

Aside from calling the builders liars (and they are) and pulling off the new gyprock to double check…. I did seem them put in new/more insulation, but I was not there micro-managing…

But in my defense….my wife tells me (at lunch today) our heating bills are not out of the ordinary. I just have a louder voice than most and not willing to take it anymore. So, I do not think I have the worst house in the town.

So Artt you can take that bit of information and do with it what you want……

The only things (and you are the expert) is windows, sealing and heat pump (probably in that order).

D

Posted Tuesday 2 Jan 2018 @ 2:31:53 am from IP #
dave lawrence
Member

yes ,we are all experts in hindsight . all the best .

Posted Tuesday 2 Jan 2018 @ 3:52:02 am from IP #
foxint
Member

Hi Dave

Thanks for the great replies. I suppose I my case to far too hard....

My original question was surrounding how, does the conversion of MJ (a volumetric measure) get to kW/hrs (a volumetric measure over time) by simply dividing it by 3.6. I cannot see the logic.

I suppose no one is going to answer this one….

As I said to my wife, simply accepting a large gas bill (regardless of it being close to the norm) is basically putting one’s head in the sand. Plus, just giving up 30K to a re-seller who says it will be alright, is not my way of quantifying a business decision.

But it has been an interesting journey. Thanks to dave and bushwalker. Window treatments have always been on the list….

I am still doing my research on which ones are the best. But from some research last year (2016) it would appear that (a) a roller shade with side track & reflective coating 25mm from the glass on the inside reduces heat loss by 55%; (b) roman shade, 2 layers fabric, plastic vapour retarder and insulating material 70%; and (c) a ridged insulation board with fiberglass insulation batt on the glass 82.5% - but this will look ugly, reduce the re-sale of the house and will not be allowed by the wife…..So we have to focus on (a) and (b)….”Cornell University” (not the comment about the wife).

If I had more money and not spent 30K on the hydronics 4 years ago, and knew gas prices were going through the roof, all would be different. We all make mistakes and I have made my share.

I am taking my spread sheet and searching for the truth. It must make economic sense. At them moment I cannot see….

Thanks

regards
Dan

Posted Tuesday 2 Jan 2018 @ 4:14:11 am from IP #
dave lawrence
Member

The relationship between one joule and the watt can be summarised as the work required to produce one watt of power per second. The calculation of Watts/hour for an appliance will give you an idea of how much energy is consumed per day. The kWh is equivalent to 1000 watt hours.

and there are 3600 seconds in an hour ...hence dividing by 3.6 .
logical .

Posted Tuesday 2 Jan 2018 @ 6:00:38 am from IP #
dave lawrence
Member

http://www.yourhome.gov.au/introduction

for an impartial expert consideration check this website

Posted Tuesday 2 Jan 2018 @ 6:07:35 am from IP #
foxint
Member

Dave

Thank you. A good explanation - thanks
Dan

Posted Tuesday 2 Jan 2018 @ 8:15:36 am from IP #

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