trying to be fair...

hvacfreak

Hey Brad..

Look at our post times , LOL ( mine below ). You got me by a min...day ( minute ) late and a dollar short ( my life..lol ). - Mike

Timco

So I hire this company to monitor the circs on my boiler @ my 4-plex. Here in UT this is legal, and the laws do provide for this type of break-down of a single gas bill for multi-unit dwellings. Problem is I just don't think everyone is getting the same deal. Unit one is 800 sq', with all CI rads. (HW system). The most EDR of any unit. Gas usage bill is $53 last month, based on circ running time. Unit two is 700 sq', and bill for usage is $40. CI rads. Unit 3 is a studio with AMPLE EDR to cover his space, (the CI rads are oversize actually) and his bill is $55. Maybe he likes it hot? And unit 4 has a usage bill of $82, but he has all Slantfin BB heat, with little EDR.

If the boiler is hot, as it typically is durring the winter months, and he needs circulation for heat more than a CI unit, should he be 'taxed' as he is being? How do I split a 4-unit dwelling more fairly with one unit using BB heat?

Thanks, just trying to be as fair as possible. Merry x-mas!!!

Tim

Brad White_163

Merry Christmas, Tim

What you say makes sense regarding Unit 4. With little EDR the circulator has to run longer trying to meet setpoint. It cannot compared to the others so it runs and runs, trying to catch up. Net result is, the unit is not extracting the heat much as you suggest. I suspect a narrow delta-T on that system.

Unit 3? Maybe likes it hot as you say or forgets to turn it down when unoccupied?

This illustrates why flow and delta-T over time is the only equitable way to apportion the bill, regardless of what your state allows.

As you can imagine, the SF of the units is only incidental and does not indicate heat loss.

Given the disparity it is almost as if you want to go back to a heat loss basis or a Net Rentable SF basis. (Higher heat loss may mean more windows and a better view hence justification for a higher heating bill?)

You may also want to monitor space temperatures and factor that in. Perhaps a WEL? Or remote datalogger of some sort?

I am sure that the tenants appreciate your consideration and being fair to all!

Merry Christmas!

Brad

hvacfreak

hmm...

I'm not sure I understand the layout of the " fourplex" ...but depending on the position of the structure versus weather patterns , the guy with the most circulator run time may just have the misfortune of being on say the northwest corner ( highest loss at my house ). I would say square ft. living space is the only way to divide that gas bill ( short of space temperature monitering and trending ). - Merry Christmas ( or a freaky one ) - M

Brad White_163

Timing is everything.....

But the good minds agree!

Merry Christmas, Mike-

Timco

Unit 4 is the basement unit with the least amount of window and / or door. It is a 850 sq' apt, 2bdrm, but enjoys the insulation of mother earth. I know the sq' is not a factor to a point, but is there some math that could be done vs. the total EDR of each unit to equal out the formula for heat distribution / usage? They should pay to like it hot, but the same rate for different EDR.

Thanks,

Tim

Brad White_163

Tim

If you could fire off an e-mail with the heat losses and the approximate EDR of each appartment, maybe I can come up with an algorithm that will be a little more fair.

I have to warn you though, I am no King Solomon... after the Fluffy the cat and sawzall event especially

hvacfreak

funny

I know that neither of us " edited " ..I reviewed my spelling , posted , and saw your reply..too funny. Merry Christmas to you as well. -M

S Ebels

Circ time not good indicator

To correctly establish the actual BTU's delivered to each apt, you'd have to measure temp drop and flow in GPM for each unit. Your guy with th BB is getting the raw end of the deal.

Constantin

There are dedicated BTU meters...

... for an all-inclusive box. They measure flow, supply and return temps, calculate the total BTUs consumed on that basis. They tend to be expensive though.

In the end it might be cheaper to make all the emitters the same. If each apartment had the same lineal feet of emitters and the same emitters, then the current scheme of splitting the bill (via circ time) might make more sense.

The least expensive way to overcome the limitations of the various emitters would be to account for the lineal feet vs. the heat transfer by type. Perhaps Brad can help you there. How it will be received by the house residents (and possibly the courts) is a different matter. Best of luck!

jp_2

piping layout?

is it possble that the BB is getting cooler water temps than the 'hot' apartment.

if all units are calling for heat, are they all getting identical water temps?

seems if its P/S those closely spaced Tees down stream get cooler water.

Rich W

I'm thinking that actual usage is the only fair way to charge.

1.Install an hour meter on each zone.
2.Count/Calculate the actual EDR for each unit.
3.Record the EDR in your log book.
4.At the end of month record the hours of usage.
5.Multiply EDR and the hours for Btu's consumed.
6.Add the Btu totals.
7.Calculate the percents and apply to the gas bill.

It shouldn't be too much trouble to make a small spread sheet for this task.

Merry Christmas.

P.S. I assume the boiler room door is locked...

Timco

Brad..

Thanks for the help...Your email address never shows up on my email. Funny thing. It has been a while since I did the heatloss, but I will re-do it and send an email off if I get your address, along with the EDR of the units and a picture of the boiler, which is direct return piped with a system bypass for a bypass.

Tim

Timco

What type of file is a xlr? I cannot find a program to open it...but am interested in your opinion / spread sheet!

Tim

brucewo1b

Timco

Microsoft Works Spreadsheet or Chart

Weezbo

this is a slightly different thought ...

did you see the New Honeywell controller?

it has Zone synchronization..that means when the longest or "leading" or Highest Demand zone is calling,....the other zones are made to function during it's Run Time..... that consequently causes the boiler to run ,.....ONLY when the long zone is being made...this in turn can garner further savings by having the boiler only run during the call rather than continuously to meet "sporadic calls" that may or may not over lap one another...

just a different thought to consider that may or may not apply ,think about it.....you see the concept.

it may be an additive set of events 82+55+53+40 ,...or any combination of the additive function or...82.....



for the heck of it divide all the numbers by nine..and round them off a bit... then you would have a 9 +6+6+4.5

so during a nine min run time you would have all zones rolling,..or it could mean that the boiler would fire for as much as 25 mins out of every run time...

i realize that systems find an equilibrium and do not deny that thought however the idea is fairly clear.

might be some savings to be shared among the tennants that made no sence to them in the past...

Timco

Am I correct in saying that @ 180*, each sq' of EDR puts out 170 BTU's?

Thanks for everything!!! Merry X-mas!!!

Tim

Uni R_2

Fairness

I'm not even sure if a BTU meter on the piping could be fair.

Imagine a stacked triplex. Level 1, heats at 70, level 2 keeps the t-stat shut off, and level 3 keeps the heat at 72 because the floors feel cool. So if level 2 stays at a temperature of 65 to 68 shouldn't they also have to pay part of the other's bill rather than just being able to leach heat from the other tenants?

Tony_23

My opinion

You're overcomplicating the whole thing. What's wrong with circ run times ? If you had one circ and three ZV's you would put an hour-meter on each ZV. How else would you split it ? Who cares if the 2nd floor tenant doesn't have to turn his up to get adequate heat ? He has to live between two other tenants, are you compensating him for that ? My sister always rented 2nd floor, the floors were warmer and the rent was less because of the stairs. Problem was, it was her brothers who carried the heavy stuff

I think you've already got a viable and equitable split happening. Quit trying to analyze to death such a simple thing. Or, you could pay the utility yourself and just raise the rent. Get a Honeywell FP5000 tstat and program the max setpoint to 72 and go with it.

Rich W

timco

Dan sells a book that tells you the EDR for lots of radiators. There is no way we can tell from here what you have. The book is full of pics so you can figure out what you have. I don't care about the actual usage or efficiency of the boiler. All this spread sheet does is figure the percent of usage and applies that to the total gas bill. I'm assuming you have a seperate meter for the heat. Counting the DHW usage will really change things if you only have one gas meter. I don't know of a high temp. flow meter- not for less than $1K, anyway...

I've done this heating divider for seven buildings in the last two years. I agree with you timco, if someone wants the heat cranked to 80deg. they should pay for it.

Once you know the radiation, that won't change.
Here is the same sheet with more realistic numbers than the test sheet I sent.

hvacfreak

envelope


Circulator run time would only be fair if the setpoint were the same in all units. Even then you would have to account for living space ( outside wall area is what it is and is a constant as far as tenants are concerned ). Space temp and square ft is the only " fair " way in this scenario , period.

Find a reasonable high space limit ( 74 ? ) , divide gas bill for ths by sq. ft living space , and call it a day ( put the rest in your pocket for maintenence ). -M

Edit : If this were a row of townhouses each unit would be responsible for what they use either way...so the circulator run time makes sense when I think about it in that respect. And someone should get a break if they set the temperature down on thier stat. End units just have a higher price to pay I guess.