Water heater improvement (Timer)

[Patrick]

Originally Posted by NiHaoMike

For a little energy saving, disable the bottom element. That will reduce the volume of water that is heated.

Thanks for the suggestion. Here is my dilemma. My tank is 50 gallons. My wife likes to take Jacuzzi baths in HOT water and the tub takes about 50 gallons to fill to a reasonable level.

My understanding of how the water heater works is that it runs on the lower element most of the time which heats the entire volume of the tank. But if you put a great demand on it by using a lot of water quickly, it kicks on the upper element to get "quick recovery" so that you're not getting excessively cold water in your shower/tub, etc.

So if I change it so that only the upper element runs, will my wife run out of hot water for her baths?

[Patrick]

If I have a lot of insulation around my water heater, will a timer do me any good? With a very slow rate of heat loss in standby (where supposedly the greatest amount of energy is used), am I gaining anything by putting the heater on a timer?

In other words, is it possible that with additional insulation the temp drop could be minimized to the point that the themostat would kick on the elements at the same time that the timer would if it were installed?

[Xringer]

A timer might help a little. Even with good insulation, it might turn on at 1AM
to keep the tank hot all night.
If you could keep it from coming on between 10 PM & 5 AM, you might save some money.
With super good insulation, the temperature isn't going to drop very low over night,
when no one is using hot water.. So, the 5AM turn on won't have to be a long cycle.

If you both work, does the hot water need to be on while you are both at work?
No one using it, temperature pretty stable.?. Turn it off between 8AM & 4PM..?.

IMHO, working people need a 7-day timer with a weekend program..
Mine is made for old retired folks..

[Ryland]

Originally Posted by Patrick

In other words, is it possible that with additional insulation the temp drop could be minimized to the point that the themostat would kick on the elements at the same time that the timer would if it were installed?

The biggest temp drop is when you use water, take a shower, wash dishes, whatever and most people do things like take a shower in the morning and go to work for 8+ hours, come home cook then wash dishes, water heaters tend to click on from the thermostat after half or so of their water is used, so a shower in the morning cools the temp of the tank down then about the time you are done with your shower and heading out the door it reheats it to full temp where you have the greatest heat loss between the 130F water and the 55F basement air, so why not let cooler water sit in the tank all day or all night while you sleep, then heat it right before you want hot water.

[NiHaoMike]

Originally Posted by Patrick

Thanks for the suggestion. Here is my dilemma. My tank is 50 gallons. My wife likes to take Jacuzzi baths in HOT water and the tub takes about 50 gallons to fill to a reasonable level.

My understanding of how the water heater works is that it runs on the lower element most of the time which heats the entire volume of the tank. But if you put a great demand on it by using a lot of water quickly, it kicks on the upper element to get "quick recovery" so that you're not getting excessively cold water in your shower/tub, etc.

So if I change it so that only the upper element runs, will my wife run out of hot water for her baths?

Sounds like the perfect application for a heat pump or thermal solar collector.

You can try turning down the bottom element temperature until it's completely off or until the water just starts getting too cool.

[Xringer]

The timer has been installed a few days now and my wife gave it the

With the oil burner running 20 to 30 minutes at 7:30 every morning,
and the Solar PV adding some heat during the day, we seem to have
more than enough hot water to meet *our needs. (*two retirees).

I'm not sure, but it seems like we have enough HW to take at least
4 showers a day. Have not tried it on laundry day, I suspect the last
shower would be luke-warm..

Over-all, this mod was good one, that has improved our quality of life.

We won't save as much, as if we ran the boiler manually, but that
method has it's problems, when you are old and forgetful.

I was getting ready to go bowling this morning and decided take
a quick shower on the spur of the moment. Not possible with manual control.

I like the idea of the boiler firing up once a day. Just in case we need
it to heat the house in the winter.. Hopefully, it will just stay a hot water heater..

[Daox]

I'd be very interested to see how much oil this saves. I don't suppose there is a good way of measuring this though?

[Xringer]

Originally Posted by Daox

I'd be very interested to see how much oil this saves. I don't suppose there is a good way of measuring this though?

It's actually going to use more oil, now that we are off the manual-mode.
Using on-demand with the switch is just too inconvenient for us.
And, washing your hands during the day with cold water isn't fun.. (65dF)

But, the total usage is not going to be super expensive, and it can be calculated easily.
Summer time use is going to be 15 gallons (or less*) a month.
At $3 per gallon (a guess for this winter) is $45 a month. Not that cheap!


* It will randomly be somewhat less, if the PV is working well and/or we don't use
a lot of hot water the day before. The burner will run a short-cycle
for 15 or 20 minutes and shut off before the 30 minute segment is over.
We have observed two short-cycle burns this week.. (Approx 20 min).

It might be cheaper to use an electric HW heater,
but we need the oil burner for back-up heat in the winter.
(Which is long in this area).
So, we are going to suffer with $45 per month until the price of PV takes a drastic drop..

[Xringer]

We didn't burn much oil during summer 2010. We got our Fall fill-up last week, 78 gallons. ($2.59 per gallon)

Since April 29, (until Nov,3) we used both the manual control & the timer.
6 months, 6 days = 189 days total, for 0.412 gallons ($1.07) per day.

~~

If we don't get too much super-cold weather this winter, with temps staying
under 10 degrees F, for too many hours, we should be able to use the Sanyo ASHP to stay warm,
and keep using 0.5 gallons a day (using timer) until the April 2011 fill-up..

~~

If it's a really bad winter, and the Sanyo averages ~10 kwh per day,
that's going to cost about $2.00/day ($60 per month).

Haha.. That really puts the cost of heating hot water with oil into perspective, eh?

~~

I should also say, that good solar days will reduce the load on the Sanyo,
(due to southern windows), and may slightly help the daily oil burn, due to the
500w PV heater in the oil burner.

[Xringer]

The burner has been bringing up the water to 170 in less than 1/2 hour.
Seem like 15 or 20 minutes on some mornings. I don't like those short cycles.

And, since the nights are getting down in the teens now, and the den had
some spots that got down to 38F this morning, I've decided to start
using the left-over heat in the burner (87 gallons of warmish water).
Why let it just dissipate up the chimney over night?
(note: The Sanyo is keeping the main living areas at a 21C 24-7)


So, each night before I sleep, I'll open the free-flow valve and let the warm water
circulate around the perimeter of the house, keeping those unheated rooms
from falling into the freezing range..



I'll have to get up early each morning and close the valve too..

If this measure isn't enough to keep the baseboard pipes from freezing in the unheated rooms,
I'll reset the timer to run the burner for 1/2 hour at 2AM..
I guess we can afford two 1/2 hour burns a day, when it's really cold..

Cheers,
Rich