Hello- I am buying an older 2100 sqft ranch built in 1971 in Essex MA. The home was built to run off electric baseboard heating, likely a result of issues with oil prices in the 70s. The house has over 2 acres and would potentially lend itself nicely to a geothermal HVAC system. The inspector noted that the house was well insulated, likely a result of the house being designed to run on electric baseboard. There is also a wood stove insert in the basement to provide supplemental heat. My question is, prior to considering any HVAC, I would like to better understand the insulation and/or heat loss characteristics of the house, however I am unsure how to do this. Can someone please fill me in on the best tests to determine what kind of heat losses the house currently suffers? I apologize if this information is readily available on the net, I haven't been able to figure out a clear answer. Any input is appreciated!

I would suggest an energy audit  like talked about here

That's exactly what I'm looking for. Are these pretty standard, or is there anything in particular I should be looking for? I know my utility company offers a free audit, however my understanding is that it doesn't include infrared scanning.

infared and a blower door test will tell you all there is to know.

I would also look at the current performance (KwH vs degree days) as compared to manual J. In most cases, the question isn't "is heat being lost here" but is "is it cost effective to do this improvement".

By far the best ROI is to improve your envelope prior to doing anything. If you reduce the load of your house, you reduce the tonnage required to heat and cool the house. If you reduce the tonnage you reduce the initial outlay and the operating expense.

With a good blower door test and thermal imageing you will learn what you need to do to reduce your load. Shop out the improvements and look at the estimated reduction in tonage vs. what you anticipate spending to make those changes with a good hvac guy and you will see the saveings.

Our website has a lot of info pertaining to this topic as we advocate tightening up the envelope prior to spending on geo.

Eric

Posted By jonr on 23 Apr 2012 09:53 AM
I would also look at the current performance (KwH vs degree days) as compared to manual J. In most cases, the question isn't "is heat being lost here" but is "is it cost effective to do this improvement".

I agree that kwh/HDD information would be far more accurate than a heat loss calc.


From a cost-effectiveness point of view...

Homes of those era in MA with electric baseboard heating tended to have 2x6/R19 or R13+5  walls, U0.6 windows, but no foundation insulation.  (I have 2 sets of in-laws currently living in homes of that era & description.)  Air leakage will vary though, and it might take a blower door test to really nail it.

If the windows are tight, but old-school double-panes of the 1970s, adding low-E storm windows to all but the south facing windows is more cost effective than buying more geo to support the delta in load (and has a greater improvement in comfort too).  If you have 150 square feet of window it would add up to 1/4-ton or more difference at design temp.  (A U0.60 thin clear-glass double-pane drops to about U0.30 or less with a low-E storm window over it.)

Depending on the type of foundation, retrofitting foundation insulation may be cost-effective as well, and is probably worth between 1/2-1 ton.


Essex is relatively warm on average compared to central MA where I live, but the mean January lows (about +16F) and 99th percentile design temps (+5F) are comparable.  This is warm enough to hit an average COP of ~2.5 or slightly better with ductless air-source heat pumps, at a fraction of the up front cost of geo. (Better class ductless hit   In a tight rectangular-footprint ranch your current heat load at design temp is probably already under 3 tons, and could be brought down to under 2.5 tons, (or even 2 tons) with judicious envelope upgrading for less than the cost of the additional geo that would have been needed to support the higher load.

At that point it's useful to do the math on going with ductless air source (with the baseboards for backup & load balancing) for a combined average COP of 2.3-2.5 & photovoltaic (PV) panels, that makes up the power use difference of going with more expensive & efficient geo at an average COP of 3.5.  Both geo & PV are heavily subsidized by both the state and feds, and the math isn't super simple (given the production credit aspect of the PV subsidy) but it's often a better investment to go air-source + PV than geo, especially when the design heat load is well under 3 tons.

If the budget is unlimited, PV + geo could make this the greenest li'l house in the 'hood.

I grew up 4 miles away in Manchester in a home built in 1964. I make certain to have a fried clams and clam chowdah and Sam Adams meal at Woodman's EVERY time I go back.

I agree with Dewayne, Dana and Eric. Take some of the longer posts in this thread with a large grain of salt.

Fundamentally what you need is an accurate Manual J heating and cooling load calculation. A blower door test will quantify and firm up a significant input to the Man J calculation, that is, the relative "tightness" of the home. Envelope improvements, up to a point, are better investments than increasing heating and cooling system capacity and run time.

Infrared thermography will aid in finding missing insulation as well as locating air leaks. Another option is theatrical smoke in tandem with pressurization using a blower door.

Effective, economic operation of the woodstove is governed by its efficiency and your desire / willingness to gather firewood and tend the stove. I did so for 3 decades before heading south.

A geo system may be a good fit for your home AFTER all low and medium cost improvements have been made to your home's envelope. Whether a horizontal or vertical loop field makes sense will depend very much upon local soil conditions, depth to rock ledge, etc.

I'll be in Manchester in early July (like to be home for the fawth of July parade). I'll trade a quick holistic building science audit for a coupla beeyahz (Ipswich Ale preferred)

Posted By Dana1 on 23 Apr 2012 05:23 PM

Posted By jonr on 23 Apr 2012 09:53 AM
I would also look at the current performance (KwH vs degree days) as compared to manual J. In most cases, the question isn't "is heat being lost here" but is "is it cost effective to do this improvement".

I agree that kwh/HDD information would be far more accurate than a heat loss calc.

I use kwh/HDD as well as heat loss calcs to size equipment.
What is important to know is while more accurate than manual J (for loss/gain in a given parameter), but manual J calcs have fudge factor for reasons.
Very tightly designed systems have a harder time compensating for terrific temperature swings. They also have a hard time when temperature drops below design temperature (unusually cold weather) climbs well above it (unusually hot weather).
Geo has the advantage of a 3rd stage, so we can design very tightly on heating and are generally oversized for cooling in MI.
Other heating appliances may not have a second or third stage so tight designs can have the consequence of not keeping up in extreme weather.

Using multiple factors to size equipment is far and away the best method.
These factors can include thermal mass of space to be conditioned.
Designer experience.
Manual J calcs.
Actual usage.
Extended weather history.
Occupants' comfort zone (even thermostats now have comfort vs economy selections that permit larger droop).

Someone who bases design solely on one factor is better off using manual J than just HDD calcs if weather goes far off the beaten track or if occupants are comfort v economy minded.

Conventional AC systems in MI are a great illustration. Where summer temp swings of 20 degrees are not unheard of, tightly designed systems that were not running the day before have little chance of keeping up with such a huge and sudden demand. HVAC installers are frequently at odds with economy minded MEs (who load share et al) on commercial projects for this very reason.

Having the accurate stake in the ground based on kwh/HDD is just that, a stake in the ground, not a maximum number to design to.

The 1-sigma oversizing error on Manual-J is somewhere around 20-25%, which can be an unnecessary and expensive design constraint, especially when (as in this case) the backup for 100% of the load is already installed. With ductless air source designing to 25% above the heating or cooling load at design temp results in about 0.25-0.5 COP higher average efficiency, and builds in significant margin, usually at a fairly modest uptick in system cost. With the higher upfront cost for geo it's more tempting to design tight to the numbers due to the higher upfront costs for that marginal capacity.

For a 2100' rancher in Essex MA already pre-fitted with electric baseboard backup, designing the geo tight to the 99th or 97.5th percentile measured heat load would not be a disaster. With the geo in combination with baseboard the conditioned space temp wouldn't lose ground even if a colder-than-design-condition excursion dropped 50F under the 100 year lowest outdoor temp. The last time it hit -75F in Essex was probably during the last ice age, yet with geo designed tight to the measured heat load at +5F they would have ample margin, yet retain 99% of the benefit of the high efficiency system without the expense of over-building it.

Wow, I really appreciate the discussion you guys have provided, thanks! I'm a details guy and this is what I was looking for. I have contacted an energy auditor to conduct a blower door test and a thermal scan. Hopefully this will be done in the next two weeks. I will post the results here for those who are intersted

Guys-

I just went to the North Shore home show and they had one booth with ductless minisplit, but the guy at the booth (won't mention the heating company) said I'd be happier installing an oil furnace then trying to heat with the ductless mini-split. He also thought that if I could afford 100-200K geothermal would be an option...

That's mostly nonsense. The price of fuel oil is inextricably tied to Diesel fuel, which has high and continuing global demand (check out the road systems under construction in India and China...2 billion people who wish to drive cars on roads resembling our Interstate system)

Minisplits have come a long way...they are excellent for cooling homes that lack ducts. I don't have direct experience applying them in heating dominated climates.

Geo is pricey up front but offers very low operating cost. That said, cost for a system to serve a mid sized home shouldn't run anywhere near $100k

Posted By sbeausol on 26 Apr 2012 07:42 PM
said I'd be happier installing an oil furnace then trying to heat with the ductless mini-split. He also thought that if I could afford 100-200K geothermal would be an option...

Yup the guy in the next booth was wrong on both counts

Posted By sbeausol on 26 Apr 2012 07:42 PM
Guys-

I just went to the North Shore home show and they had one booth with ductless minisplit, but the guy at the booth (won't mention the heating company) said I'd be happier installing an oil furnace then trying to heat with the ductless mini-split. He also thought that if I could afford 100-200K geothermal would be an option...

You should be able to get the heat load of a house that size with simple exterior lines (not 14 dormers, 5 bump-outs, etc) under 3 tons @b +5F in which case you'd likely be paying in the ~$20K-$40K range for geo, barring anything unusual.  At 4+ tons don't count on getting it under $30K.

For $200K you could buy a quarter-acre of solar PV and heat with your baseboards :-)

Most homes in this area heated with mini-splits/mulitsplits need some sort of backup, but you already have that backup installed.  At your mean January low temp a ductless has an average COP of ~2.5, and at your January average temp it'll run closer to 3.0.   If you need to run the baseboards when it's 0F outside to stay warm it isn't going to affect your seasonal performance very much, since that's less than 1% of the hours in a heating season.  If you need to run the baseboards in 1-2 rooms for balancing the temperatures it'll cut in a bit more.  If the ductless can carry the entire load your average COP will be about the same as the COP at your January mean low, maybe slightly better, but not a lot better.  With baseboard balancing and for peak lows, figure on ~2.3.  A 3-head 2.5-3 ton multi-split would still usually be under $10K, installed.  A single-head 2 ton mini-split is usually under $6K.

With geo, factoring in all pumping air handler power you can expect a system-COP to average ~3.5, which is substantially better efficiency, but substantially more money up front.  With ductless you're getting ~2/3-3/4 the heat per KWH, but it's only 1/4-1/3 the upfront cost. 

If you can cut the heat load by 1/4-1/3 with the difference in up-front cost and going ductless you're using about the same amount of power, but you're in a tighter/warmer/more-comfortable house for the same up-front cost. And the life-cycle cost of the building envelope upgrades exceeds that of the heating system.

With a 3 ton heat load @ 5F and an average COP of 2.3 (mostly ductless + middlin' use of baseboards) and 18 cent electricity your annual heating costs would run just about $2000 in a typical 6000HDD year.

With an average COP of 2.5 (multi-split, minimal baseboard use) it would be ~$1825.

With geo it would run about $1300/year for a 3 ton load, but with a 4 ton load it would be about $1750. 

Ductless at a 4 ton load @ 2.5 COP would run you ~$2450 annually.

The difference in the 4-ton load scenario is only about 4000kwh/year, which is an amount than can be sourced by a ~3kw (peak) grid tied photovoltaic array (if you don't have serious shading factors.)  Without subsidy a 3-4kw PV array is likely to cost LESS than the cost delta between a 4 ton multi-split and 4 ton (unsubsidised) geo.  (This would not have been true even as recently as 3 years ago, but it is now.) Compare subsidies, but in many cases even subsidized geo may still cost more than the un-subsidized PV that covers the difference.  But still, taking all of the low and mid-hanging fruit on envelope upgrades is usually the best first-cut, then sharpen your pencil on the rest.

If you're re-siding, re-roofing, or building on an addition, these are opportunity moments for envelope efficiency upgrades that would not make financial sense if energy savings were the sole purpose for the project, but can make a substantial impact on both average and peak loads for a marginal uptick in project cost.

Dana-

Thanks for the input. My intention was to consider both mini-split and geo. Does anyone know reputable contractors in my area (Essex MA 01929)?

If family needs 100% HW and you want to deduct HW equipment-
~~~~~~~~
Like history of a larger home, but yuite lower in KWH in -12-below  winters:
Yesterday saw a third time, 2003 installed
( what comparable KWH's, D1)

  8yr avg zone 5.1/2  but the bundle: HVAC-GT-HW-Recovery100% : under 8000 KWH's annually.

Dual compressor "size 4.5" by rated's standards 3-Function GeoT System, RECLAIMS 100% HW heat from Cooling mode

3400 sqft, 240+ glass, 1998 construction, but tight, but uninsulated 1/2 basement, 2 Story Colonial/ fireman-wood-crafter

A sandy -well chipped away at 2 aircoils and Had 17: TETCO tube-shell 5 ton hx on  4-ton heater only with water-well-cooling 4-ton ch water coils "poor dehum"  found 2 gpm per ton (below 3-3.1/2 used today in direct 'clean'-WellWCooling)
all replaced 2003~ two-sets of screen filtering is saving system.

Their notes
on a clip board in basement
oct 2003 ( having 3 HW-cleanout , quick check calls to date, only-)
0 kwh
on meter to compressors only for 100% HW and Heat Recovery in Cooling and Heating-some DeSuperheating

open 52-deg water :   (only met when sold in 2003)

67000 kwh... 
 this is like another 3400 with fam of 5 averaging 8800 since 1996, open well 5-ton 8gpm, water within 60ft at dynamic level peaks.

3-speed selected ECM-blower motor, HW at bottom-tank sensor set 116 deg. has temp valve 122, because convected water flow, desired to not have a presenter, - tank hits near 130, he claims.

ALL HW HEAT AND COOL using NO SUPPLEMENTAL HEAT to -17 and -18 deg spot zone 5.1/2 in NE OHIO 6500-6600 deg days.

says he uses house setting 74 in winter, as a flywheel to 65 and 64 nights inside the home.

~~~~~~

Harris burg PA $ 93/mo all electric bill would probably only be ~ 130/mo mini-split: back-calculated, HW costs go up, then.
2400 sq ft some radiant 4Synergy(TM)series   all 4 functions, one over-sized size 5 dual compressor, their choice... 3 zones w/ bsmt
Loop never below 38-deg, ever in 4 winters.

Want some comfort-radiant in just a few areas?
Want HW recovery 100% in cooling at low stages?
2-Compressor-ton  single 2 speed with Desup-Hybrd, ~ 7 gallon per hour recovery WHEN RUNNING avg'd out:
or for $ 1300 more installed than DSH installed with CLEANOUT-Drains (after credits 30% if qualified):
You may then have 100% HW and in Cooling: reclaim system heat from the home

oh:
it then has a 4-zone control board installed OEM so deduct 100% instant HW or additional tank or zoning system other than litle dampers, or valves for some radiant...

but for never using supplemental:
Dual compressor is really getting a 20-year recovery , on the 2000 adder,  "3-ton is with 40k total  compressors in the COP 3.6 including pumping system of 1   180-watt circulator box
and
COP's of 5 or more b/c over-sized  HX air and water coils on a low speed comparison.
add ~ 1400 more that way plus the 1300 with HW tank inclusive anf installed

Can contact Enertech GBT directory for TETCO or Hydron or GeoComfort
and
800-382-3113 www.Hydro-Temp.com

JP

www.GEOPros.com

Posted By sbeausol on 28 Apr 2012 09:22 AM
Dana-

Thanks for the input. My intention was to consider both mini-split and geo. Does anyone know reputable contractors in my area (Essex MA 01929)?

Local certified installers for ductless can be located via the vendors' contractor websites, and some will even rate the contractor based on consumer feed back or levels of training, # of units installed, etc.

http://www.mitsubishicomfort.co...17&go.y=10

http://www.daikinac.com/commercial/...omerun.asp

http://dealers.fujitsugeneral.com/d...N=10185933


Get at least 3 proposals, and pay an independent contractor to run a room by room & whole house Manual-J on the "after" picture on your intended building upgrades, and have them specify the load at +5F (your design temp) and 15F or 20F.  Look at the output curves or specs across temperature for the units and try to find a solution that delivers your house's load at 20F or lower at that temp.  (The nominal heating rating is usually at 47F, but it'll be lower at 20F. Most specs will have a +17F  heating output number as well.)

Most competent installers will run their own heat loss calculations, and will charge you something for it, but most would accept another's detailed heat loss calc unless it seemed obvioiusly way off.  "Free" proposals are often worth less than you pay for them- it takes time to do it right, but getting it right pays dividends in comfort and reliability.  Oversizing a ductless by 25-50% usually results in higher efficiency, but going too high results into a drafty feel from higher cfm interior heads.  Locating the heads where they won't blow directly on seated occupants can sometimes be an issue, depending on the floor-plan/layout, but there are usually reasonable placement solutions.

Geo contractors are a rarer bird to spot, but most will travel some distance for a project.  Maybe someone here can recommend? Design competence is more important with geo than with ductless, with many more factors to consider to getting it right.  Ductless are pretty much "systems in a can", with the engineering aspects pre-determined- air is air everywhere, but ground conditions vary signfigicantly by location.

The output air of geo tends to be on the very-tepid side, an locating the output where it won't blow on people is even more important than with ductless air source.  (Ductless heat pumps were originally designed for Asian houses, where the quarters are much tighter- too tight to assume they wouldn't blow on people, so the output temps are typically above 100F, whereas with geo exit air is often under 90F, necessary to maximize efficiency.)

as the tepid conservatism of the fifties, "just some warm" so is a FIXED system relative to HtP HX warmth at say where it dro[s sig nificantly right at 17 after the 47 but slopes down in heat production between: Colder source:colder output temperatue with less work done.

With the major brand referencing Hydro-Temp (.com to see)
the MODULATING PROGRAMMABLE blower
~ enough said?

set 96 at the air-handler, get 96, off the wireless palm(tm) interface

Customer can reprogram in 2 minutes, seasonally , and different stages independently, EASIER THAN A STAT !

HIGH rating 500 cfm/cooling ton to imagine only 325/ratings tons
or 340 cfm per cooling Compressor-actual ton
with over-sized air coils such as most the 'major brands' have followed to so do-
WRINGING MOISTURE OUT OF THE AIR
but  going into cooling with 100% HW on a cold GT Loop seasonally, SEERS can be well over double other A:HtP eff

This IS the system
that the "7% lower expense than GT" does not take in to comparisson.

BUT data for estimated 7- 10 years should be estimated all machines and HW tanks to all apples.

I like mini data !!!

all is why I will keep asking for annual HW KWH or therm comparison WITH A:HtP and maintenance for 30 years
of COP's 3.6 to over 5 - easily, using BOTH sides of all the thermal energy transfer at ONE TIME.

at significant lengths of annual cycling

Your comfort is precisely your choice.
Your air-plumbing / as ducting and distribution might be easily made better with sealing and balancing.
What can help is just ask for the bundle :  HVAC-HW-Recovery

Multi Staging now since 2007 programmer as in the PA
TOTAL ALL-ELECTRIC BILL $93/month
2700 including 1/2 of the walkout basement icf
- with a 100%HW system allows some now or later RADIANT options under cold toezies on say, tile flooring.

JP

Posted By Dana1 on 28 Apr 2012 12:03 PM
The output air of geo tends to be on the very-tepid side

Nice Dana! It has been a while since you have referred to geo air as "tepid". You used to call geo air "tepid" in just about every post. I guess that is why you needed to say "very-tepid" this time.