TRV + Conroller = How much Savings???

Chuckles_4

There ya go. "Why don't you EXPECT to see reduced fuel consumption from this?" It's not a question of believe, expect, think, feel, guess, etc. It's a question of HOW MUCH one will save.

You can find lots of people who say they are saving money from setback, but has any one of them made a rigorous measurement? No, people "feel" they are saving money, and so they may select data points that "prove" they are saving money. I am not saying they are losing money, but the savings aren't significant in a real house. The money will buy you a coffee at Dunkin' Donuts, but not at Starbucks.

If you overheat the upstairs, you need more BTU to do that, but most of that BTU leaks out to the downstairs! (The floor between them is not insulated, but the outer walls presumably are.) When you put in a TRV upstairs, you need to heat the downbstairs more. There is indeed reduced loss through the outside wall, but it is small change. You won't make the $180 back with interest in a hundred years. (Incidentally, that $180 is per TRV, you didn't do your entire upstairs for $180 unless you have only one upstairs radiator.)

If feelings and expectations were scientific, the world would actually be flat. Unfortunately, people are persuaded to pay real money for upgrades that won't save real money. The Televangelists of Hydronics are selling an unverifiable promise, but they are asking for real money.

I am not denying that TRVs are great for comfort.

Derek Kolakowski

First off.. thanks everyone for all the information on my last question! Its certainly the best response out of all my experiences on any help board!

Now... the next step is trying to sell work and parts to the Condo Association. Can anyone tell me where I could find some basic numbers on how much of a change in heating costs/requirements installing a boiler controller (tekmar/heat-timer) and/or TRVs on my one-pipe steam heat would create?

I know the numbers would be dependant on my current settings, my settings after installation, my system, and my building but I need to find a crow bar with which to pry open the coffers.

Already, with the preliminary info I have provided them they are asking about recouping the costs within this heating season. Last winter we spent somewhere between $13 and $15k on fuel oil so I don't think is reasonable since we are looking at $5k worth of upgrades. But if I could show them we could recoup it over 2 or 3 years...

And I know a pro could probably do all this within about an hour but again, the purse strings are pulled about as tight as they can be and I don't want to get anyone involved till I am 75% sure they are going to spend the money.

Any ways, thanks in advance!
Derek

bb

Derek:

On average you can save between 10 - 20% by installing TRVs.

bb

R. Kalia_6

You won't save very much. Anyone who gives you those numbers is handing you the standard wethead line. You'll get increased comfort, definitely, but savings, no.

This goes against what everyone here says, but if you ask them for numbers, studies, they'll waffle. They'll say "It stands to reason that there should be savings". They'll say "I FEEL it is better to install these things". They'll say "You'll save UP TO x%". Sure, you could save up to 100%. But you won't.

This is wethead religion. It's faith, not proof. Just as you may (or may not) meet your dead relatives after you die, you may (or may not) save some money after you update your system. But you won't know until after you've paid. Try to get someone to install a system under a contract where you'll only pay if you save 10-20%. Good luck with that!

Enough

Moo,

I have an upstairs that typically overheats all winter. BTU's are leaking out where I don't want them to. Once they are in my room they exit the house faster because heat transfers by the extra 10* temp difference.

I just installed TRV's on the upper floor and already they are keeping the radiators as regulated. The Btu's are heading back to the boiler. Why don't you expect to see reduced fuel consumption from this? I only have to make up $180 in fuel and I don't need to do it this year to be happy.

Steve

jerry scharf_3

package deal

Derek,

Here's how I would pitch this to the assn.

The amount of savings from TRVs depends on the degree to which units overheat. Think about the costs every time someone has to open a window because their rooms are too hot. They are mostly about comfort, making the tenants really comfortable. That can reflect in the resale value, especially if the unit is sold during the winter.

On the other hand, getting all the near boiler piping problems fixed can make a major difference in operating savings. You should also inventory the radiators in the building and make sure the boiler is the right size. Replacing a boiler that is too large may have a quick ROI. It's anecdotal, but there have been reports of dropping the bill over 25%. With oil being a good bit higher than last year, and probably going up and not down over time, the numbers look better and better.

Put them together and get people on both sides. Just ask them whether they ever have to open the windows in the winter because the room got too hot. Where do thay think that heat they are dumping comes from (their checkbook.)

If you swag a 20% savings for boiler and TRV savings, and your going to run 20K for oil this winter, you can drop 12K and get a 3 year ROI. Given that the money is invested in the building rather than the oil company, the longer term just makes sense.

jerry

Enough

Moo,

Speaking of expectation, plain coffee at Starbucks is less expensive than DD and doesn't taste like styrofoam.

$180 was required to do 3 bedrooms with TRV's. I have a wrench.

Raising the design temperature difference in my house raises the heat load from 53600 to 62600 BTU/h. The upstairs would be half of that or 4500. That alone is more than 8%. Heat transfers proportionately to temperature difference so the smallest heat loss will be to another room. The dominant transfer will be to the outside.

I spent the 180 for comfort, but now that I see the actual calculated numbers, i am glad to have a payback.

Steve

Chuckles_4

Yes of course, if you can do the plumbing, TRVs are no-brainers.

Mike T., Swampeast MO

Must Disagree

TRVs definitely offer the opportunity for energy savings. If the upper floor is overheating, it's loosing signifiantly more heat through the ceiling and windows where most heat loss occurs.

Can't follow your reasoning that the downstairs will have to produce more heat to compensate.

TRVs also offer the easiest way to deeply set back unused spaces.

When combined with constant circulation TRVs maximize the radiation of any emitter. If you have the potential for lots of radiation (say old oversized standing iron) you can honestly lower the general space temperature somewhat without affecting comfort.

More than any other reasonable control system, TRVs allow custom-tailoring of room temperature to the rooms' purpose. They will also respond to other heat sources (say in a kitchen) and overheating is greatly reduced.

REALLY difficult though to put a number to the savings. If the old double-hung thermostats (windows) are being used to regulate temperature you can expect SIGNIFICANT savings. Beyond that, savings are maximized with efficient operation of the TRVs.

TRVs are different than traditional wall thermostats and most Americans won't be familiar with their operation. In a condo-type location it will be a VERY good idea to provide instructions to owners. It will also be a good idea to properly set the limiting devices on many TRV actuators. Truly no need to allow 85 degree temps in a space... Highly tamper-resistant models are available, but even the standard actuators require some time and effort to defeat the limiters.

Chuckles_4

> Can't follow your reasoning that the

> downstairs will have to produce more heat to

> compensate.


If upstairs is 80F and downstairs is 70F, heat is flowing from upstairs to downstairs (by conduction). It's the same reason a basement isn't as cold as the outside world, even if there is no heat source there.

If the upstairs is now kept at 70F, the heat downstairs must run a little longer to make up for the loss of ceiling heat.

> REALLY difficult though to put a number to the savings.


What I said.

Enough

Moo,

> > Can't follow your reasoning that the

> _BR_ > downstairs will have to produce more

> heat to _BR_ > compensate._BR_

>

> If upstairs

> is 80F and downstairs is 70F, heat is flowing

> from upstairs to downstairs (by conduction). It's

> the same reason a basement isn't as cold as the

> outside world, even if there is no heat source

> there.

>

> If the upstairs is now kept at 70F, the

> heat downstairs must run a little longer to make

> up for the loss of ceiling heat.

>

> > REALLY

> difficult though to put a number to the savings.

> _BR_

>

> What I said.

Enough

Moo,

"If you overheat the upstairs, you need more BTU to do that, but MOST of that BTU leaks out to the downstairs!"

My numbers show that with 2x10 joists on 16" centers, uninsulated that if the full delta T was on the joists, which it isn't, that construction will only pass .171 btu/hr/sf. With 600 sf at this temp difference, you have 102 btu/hr going upstairs to down. Add ceiling, floor and any floor covering and that number drops and drops. Compare that to the 4500 btu/h saving I have already calculated. Look at the NUMBERS and tell everyone where the extra heat goes.

"There is indeed reduced loss through the outside wall, but it is small change."

Do your calculations show different?

"When you put in a TRV upstairs, you need to heat the downbstairs more."

Making a statement more definitively does not make it true.

"If upstairs is 80F and downstairs is 70F, heat is flowing from upstairs to downstairs (by conduction). It's the same reason a basement isn't as cold as the outside world, even if there is no heat source there."

The reason a basement is warmer is that the heat loss is mainly through conduction into 45* dirt when it's 0* outside. Oh, and there's a boiler and piping in it too. Heat loss from your upper floors is mostly radiant to the outside which is much colder.

"REALLY difficult though to put a number to the savings."

For some more than others.

"This goes against what everyone here says, but if you ask them for numbers, studies, they'll waffle."

Who's making waffles? The reason that contractors think it is difficult to quantify is that it is. Insulation, windows, infiltration, room shape all play a role. If the HO has lower fuel bills will they turn up their thermostat a little? The FACT does not change that if all things are equal, adding less heat to water will require less energy. I have numbers that match my structure. No contractor or homeowner is going to hire an engineer to justify a $500 TRV job on a residence. If the homeowner is going to withold payment if the savings aren't exactly what they were told, the contractor will not take the job.

To Derek, you need to determine why you are going with TRV's and what the consequence (open windows, overheating, etc) of not having them is. Once you know what the response to poor temp control is, you can assigne a value to that based on changing your heat loss parameters to match the goal vs. the current situation. Assign a likelihood that so many percent of the units will have the problem you are solving and that will be the *educated* guess of your savings.

But, that's just my opinion.

Steve