Seattle oil to gas conversion

Fulham

This is for a small 1950 house in Seattle. 1580 total square feet, but 640 of that is in a mostly unfinished basement, so the real living area is about 950 sq ft. Just my partner & myself live in the house.

Seattle is big on conservation & trying to be as carbon neutral as possible so they have been offering free home energy audits. According to the audit:

• the attic is insulated with cellulose at better than R-38.
  
• the air leakage “Average”
  
• the windows, albeit the original ones with storms, are good & tight
  
• heating uses 17,100 kWhe (calculated, not actual)
  

Construction is stick with 4” brick facing. I plan on insulating the cavities with foam. If the boiler hadn’t broken a month ago I’d probably have done that first, so it’s on the list for next year.

Currently have an oil fired Arcoliner JBN12 “Net sq ft not to exceed 420 gall. Max firing rate per hr 1.25 gall” with a more modern Riello burner & a 50 gall electric hot water heater.

Using the Slant Fin app for heat loss I get a grand total of 22676 btu/hr @ 180. 3650 of that is in one room in the basement that does have a radiator, but is rarely used. I’m thinking of decommissioning that for the moment (more on that below). I chose to *not* include insulated wall cavities in the calculation even though I’ll be doing that in 2016.

There’s 27’ of copper pipe with aluminum fin baseboard in the living/dining area. 13.5’ of in-wall radiators over the kitchen, bathroom & two bedrooms. Monoflow system. Pipes in the basement are mostly not insulated.

Longer term plans may involve finishing the basement and adding a second zone for it.

I just signed the contract with the utility to convert to natural gas so sometime this summer it goes in.

I've had three contractors stop by (oil company, plumber who specializes in radiant heat, and a guy who only does boilers/radiant). Unlike back east very few houses here have radiant heat. No one has given me a heat loss calculation, but all of them took detailed notes, looked at the radiators, windows & so on, so maybe…?

I’m 99% convinced I want indirect HW.

1. (liked the guy the best) was an ES2-3 with a Superstore 60 gall. Included chimney lining (Seattle code requires it) and a temp mixing valve.
   
2. was an ES2 with a Superstore Ultra 50 gall. No chimney liner till I questioned him and he said oh yeah we can do that for $way-too-much-money. hmmm
   
3. was a guy who doesn't believe in indirects. He wants to put in a Buderus GC124 18 (includes chimney liner), and a Bradford White water heater, OR a NTI Vmax 110 optionally with a sidearm & a Trin & Stor 40 gall.
   

No one has mentioned outdoor resets.

Questions:

1. Seattle’s cloudy Most of the winter the temperature fluctuates only around 10 degrees between highs & lows. We may have a couple of cold snaps, but its really benign. Is an outdoor reset worth it here?
   
   
2. With the size of the house, and the type of radiators, will a mod con work, especially once the walls are insulated? I hear differing opinions.
   
   
3. Are the units sized correctly? They seem to be the smallest the manufacturers produce so I guess they have to do?
   
   
4. And thinking of eventually heating the basement, (about 3’ of it’s above ground), do those suffice?
   
   
5. Haven’t heard much about the Vmax. Opinions?
   

Anything else to think of? I

Thanks for your help, and sorry to be such a neophyte. We all have to start somewhere I guess.

RobG

If I were in your shoes I would call Paul Pollets with Advanced Radiant Technologies, he will steer you in the right direction. He will definitely do a heat loss (maybe not for the initial estimate but prior to selecting equipment). He is one of the best radiant contractors in the industry. You are lucky to be in his area. You can do a search on THE WALL to see some of his jobs. I'm sure others will agree. JMHO

http://www.advancedradiant.com/

SWEI

I'll second the suggestion above, and add that you should seriously consider insulating with dense-packed cellulose instead of foam.

Paul48

Hat.........I get a blank page. Maybe it's just me. I get the Elite FT as commercial and too big?

RobG

I would use what Paul recommends and services.

Fulham

RobG: Thanks. I searched for contactors here, but no one within 100mi came up. I'll give Paul a ring in the morning.

SWEI: Understand the cellulose, the energy advisor pointed me to foam simply because of the brick exterior. Cellulose is that much better to have to deal wth the hassle of drywall work?

Hatterasguy: Awesome. After reading a lot here I was thinking the suggestions seemed too big. Honesly we use a wood fireplace insert in the living room and that often provides enough heat on its own. Especially as we like the bedroom cool (just keep the door closed).

Could my calculations be wrong? Slant Fin said to use 32 degrees as the outdoor design temp. It does get down to 20 once in a while. I think single digits have been seen, but not for years. Usual winter nighttime low is probably somewhere between 32 & 37.

So much info is northeast based that its hard to extrapolate out here.

The smaller unit will still work once I do the basement? I guess it will just modulate less and dhw override will kick in if needed?

Attached the Slant Fin numbers.

RobG

I know you said you would call tomorrow, but run your numbers by Paul who knows the area and the equipment and parts availability. He probably won't be the lowest bid, but from the load you came up with and the boilers quoted, I wouldn't let those contractors in any friend of mine's home. I am just saying this as an east coast contractor with no stake involved. I think I may have met Paul once at an Uponor training class in the ninety's, but his work is well known and executed.

SWEI

Fulham said:

Understand the cellulose, the energy advisor pointed me to foam simply because of the brick exterior. Cellulose is that much better to have to deal with the hassle of drywall work?

Not sure what hassle you are speaking of? Insulating existing wall cavities with any material will require accessing the cavity in some way. A 2-3" hole near the top of each bay is usually adequate for this. One advantage of blown-in dry material is that it does not expand, which dramatically lowers the risk of drywall bulging/popping.

Cellulose is the only blowable/sprayable insulation I am aware of that does not have massive class action potential hanging over its head. It breathes, but when installed to proper densities it will stop infiltration. Think Gore-Tex.

I would never spray foam my own house, other than using small amounts as a gap filler for envelope penetrations (windows, doors, pipes, etc.)

Whenever you modify an existing wall section, you must pay close attention to where the dewpoint lands in the assembly.

Paul Pollets

Here's an Arcoliner we removed last week and will put in a Viessmann Vitodens 200 and VitoCell 300 -80g indirect in N. Seattle today. We'd have the system up and running by Wed., but we're attending Dan's seminar in Bellevue tomorrow. This house is substantially larger than yours, but we do know the correct path to comfort and efficiency....

tim smith

If you need any additional assistance we could probably help. Reed Wright Heating Company. Seattle on Queen Anne. We install 95% condensing modulating boilers. Usually Triangle tube or Lochinvar firetube boiler. Our office is 206-283-1234

solradman

We are located about an hour south of you depending on where you are in Seattle but have to say I hate driving in there as traffic sucks. Both ART and Reed-Wight are good people. Your heat loss numbers, Seattle design is 21 degrees, rough guess 20 Btu's sq ft top floor, 8 to 10 or less in basement, you will be looking at a small boiler. Love TriangleTube mod/con boilers but with your homes baseboards and wall units you will not get much reset and will never see the high eff numbers of mod/con's, but the turn down has some advantages. Look at the Weil Mclain's CGi-25, 50k in/42k out at 85% eff with a 50 or 60 gallon indirect. The high mass will keep it from short cycling and you will want the 50k for hot water. Oh yea, the Weil Mclain is half the cost of the mod/con and will out last it.