Fixing the Pretty Good House. Marc Rosenbaum, P.E. South Mountain Company West Tisbury, MA

Transcription

1 Fixing the Pretty Good House Marc Rosenbaum, P.E. South Mountain Company West Tisbury, MA

2 Specs West Tisbury, MA location One of 16 houses in Island Cohousing, developed, designed, and built in by South Mountain Co. 1,589 gsf plus full basement 1 XPS sub-slab; R-19 batts in first floor framing; 2x6 walls w/cellulose; 2x10 rafters w/cellulose Thermotech fiberglass windows, dbl low-e Ar 919 CFM50 Composting toilet Buderus oil boiler w/indirect DHW tank Gas range; dryer; VT Castings heater Salvage cypress trim in/out; white cedar shingles; hardwood and slate floors; skim coat plaster

3 Floor Plans

4 Interior

5 Energy Usage Previous electrical usage is unknown Previous occupants used an average of: gallons of fuel oil per year gallons of propane per year Thermal fuel usage is 45 kbtu/sf/year If electric usage was 6,000 kwh/year, total energy usage would be 58 kbtu/sf/year, slightly higher than New England average of 52 kbtu/sf/year

6 Goals No on-site fossil fuels Electrical zero annual net energy Thousand Home Challenge participant (

7 Constraints and challenges Best time to do a DER is when finishes or cladding surfaces need renewal House 5 has excellent finishes inside and out Easiest/least cost DER is on a simple shape House 5 has seven roof planes and sixteen corners Best return on a DER is for high usage homes House 5 has average usage and better-than-average envelope Not a good DER candidate!

8 Envelope

9 Renter strategies Blower door Zonal Pressure Diagnostics to determine how much leakage and where Showed 4-5X leakage to basement than attic Sealed bulkhead door RO, basement window RO, attic hatch, and added exterior door sweeps Reduced leakage from 919 to 650 CFM50 in 2-3 hours of work With only 2 occupants, we didn t need the 1 st floor bedroom, so we kept the door closed and the thermostat at minimum setting We ran the 2 nd floor with the thermostat at low 60Fs We ran the main floor at 62F at night and when unoccupied, and at 68-70F when occupied

10 Attic insulation re-work Settling Suspended catwalk for access Leaking

11 Attic insulation re-work

12 Basement insulation First step, move stuff away from the concrete walls Two layers 1 polyiso, top layer Thermax Spray foam at rim joist

13 Basement insulation

14 Basement insulation Hilti IDP fastener! Tools of the trade!

15 Basement insulation Two layers, offset joints, Taped seams of finish layer!

16 Basement insulation Closed cell spray polyurethane foam!

17 Movable window insulation Double cellular shades with side tracks and seals Can cause condensation on the glazing This one is translucent; light-tight available, more R value!

18 Current blower door results 0.10 CFM50 per shell sf!

19 Systems

20 Oil boiler performance Oil usage was estimated using a Hobo state (run time) datalogger on the oil burner For one week in February, average outdoor temperature of 31F, the boiler consumed 2.8 gpd of fuel oil for heat and DHW Later in February, the boiler was making only DHW, and consumed 0.6 gpd of fuel oil This is about 10% overall system efficiency for DHW!

21 Minisplit heat pump Installed a Fujitsu 12RLS single zone minisplit heat pump Most efficient minisplit, COP of 3 or more Basement temperature dropped 10F in 1-1/2 weeks Upper level 2-4F lower than main level Setback not as deep as with the boiler (66F vs. 62F)

22 Minisplit heat pump Heat pump consumed about 13 kwh/day in January 2011, or about 45 kbtu/day This compares with ~2.5 gpd of fuel oil, or about 347 kbtu/day With Primary Energy Factors of 1.1 for oil and 3 for electricity, the heat pump uses 35% of the primary energy of the oil system Cost of energy for the heat pump is about 25% of the cost of the fuel oil

23 Electric water heater Installed a Marathon electric water heater, and reworked DHW piping so manifolds are below bathrooms DHW water meter!

24 Bye bye oil And propane dryer and heater too CFM50 dropped to 465

25 Heat pump water heater Geyser stand-alone unit uses the lower electric element thermostat upper element and thermostat still active Summer 0.12 kwh/gallon, winter 0.25 kwh/gallon Low DHW usage (average gpd) contributes Modest cooling/dehumidification of basement

26 Lighting and appliances

27 New refrigerator Installed a new refrigerator reduced usage from over 650 kwh/year to perhaps 300 kwh/year!!!!"#$#!%&'()*+(*,!!!!!!!!!!!!!!!!!-(.()/0!0/1!2)&3454,6!)(+&'/0!&7!,346!0/5(0!5(7&)(!8&*69+()!29)83/6(#!!!!! 8'9+$1'+&#3+SN+''T'+) )) )UB#3%&#$>)V'9+3"#) )) )<3/S;3B0#'()N+''T'+) )) )E$#=3B#)<=+3B1=S#='SV33+SW>' ) )!"#!"#$%&#'()*'&+,-)./'+&#$01)23"#) "#))))))))))))))) 456)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))476))))))))) 23"#)8&01')39):$%$,&+);3(',") <=')'"#$%&#'()-'&+,-)3/'+&#$01)>3"#)39)#=$")%3(',)?&") 03#)&@&$,&A,')&#)#=')#$%')#=')+&01')?&")/BA,$"='(C) ""#)DE=)!"#$%&#'()*'&+,-)!,'>#+$>$#-)F"')!! :&9)!8&6,!1400!.(2(*.!&*!;&9)!9,404,;!)/,(6!/*.!96(#!!!!!!!!!!!!!!!<&6,!)/*=(!5/6(.!&*0;!&*!+&.(06!&7!64+40/)!8/2/84,;!14,3!/9,&+/,48!.(7)&6,>!!!!!!!!!!,&2?+&9*,(.!7)((@()>!/*.!14,3&9,!,3)&9=3?,3(?.&&)?48(#!!!!!!!!A6,4+/,(.!&2()/,4*=!8&6,!5/6(.!&*!/!BCCD!*/,4&*/0!/'()/=(!(0(8,)484,;!8&6,!!!!!!!!!!!&7!EC#FG!8(*,6!2()!HI3#!!!!!!!!!!!!!!!!!!!!!!-&)!+&)(!4*7&)+/,4&*>!'464,!111#7,8#=&'J/2204/*8(6#!!!!!!!!!!!!!!!!!!!!!EKDLMBNMOCCM! );3(',G"HI))))))J<KLMNO<P) J<KLMJO<P)J<KLMKO<P) J<KLMQ2<P)J<RLMQ2<P) J<KLM!O<) ))2&/&>$#-I)LMCL)2BA$>) N''#) kwh per Day /26/11! 7/26/11! 8/26/11! 9/26/11! 10/26/11! 11/26/11! 12/26/11! 1/26/12!

28 Induction range Installed an electric range w/two electric burners and two induction burners faster, more controllable than gas! Gas range usage was 192 kbtu/month Electric range usage has been 53 kbtu/month (28%)

29 Lighting Cree (Home Despot) LED retrofits in kitchen and entry

30 Renewables

31 Solar electricity 4.76 kw Sunpower solar electric system

32 Measurements Utility meter PV generation Heat pump Electric resistance DHW HPWH Composter fan Range Refrigerator Chest freezer Computer and peripherals Water meter gallons/day

33 Measurements Commercial utility meter received and delivered Export! Import!

34 Measurements PV Heat Pump Inverter Range DHW

35 Data Heat Pump kwh vs. Heating Degree Days PV Heat Pump 40 Inverter Range DHW HDDs HP kwh /23/11! 12/25/11! 12/27/11! 12/29/11! 12/31/11! 1/2/12! 1/4/12! 1/6/12! 1/8/12! 1/10/12! 1/12/12! 1/14/12! 1/16/12! 1/18/12! 1/20/12! 1/22/12! 1/24/12! 1/26/12! 1/28/12! 1/30/12! 2/1/12! 2/3/12!

36 Data Temperatures PV Heat Pump F Inverter Range Main Upstairs 30 DHW Basement Outdoors /22/2011 2/5/2012

37 Estimated energy budget Load kwh/year Heating - Fujitsu minisplit heat pump 1,700 DHW - Marathon plus Geyser 1,000 Refrigerator ft3 chest freezer 280 Composting toilet venting 184 Range/oven 200 Lights/plug loads 913 Total 4,602 PV generation 6/9/11 2/4/12 4,098 kwh Consumed 6/9/11 2/4/12 2,442 kwh Net export 6/9/11 2/4/12 1,656 kwh

38 Data 800! Energy flows by month 600! kwh 400! 200! 0! -200! PV Range Inverter DHW July August September October November December January Heat Pump Heating Water heating Refrigerator/freezer Lights/cooking/plug PV Net -400! -600!

39 Next steps Wood heat is a complement to the heat pump heat pump is most efficient in less severe weather, wood stove works best in cold weather (and when there isn t power ")!

40 Next steps Replace the two exterior doors with doors that seal, insulate better, and have higher glazing performance Try interior storms on smaller windows (insulating shades are good for mulled windows that are too large for interior storms) Probably a single collector solar hot water system

41 Transportation

42 Key learnings Occupant choices about operation of the home matter Best minisplit heat pumps use less primary energy than fossil fuel systems, and meet their claimed COP Most boilers are inefficient at making DHW when not making heat low mass matters Induction cooking uses a smaller fraction of energy than expected than gas suspect heat-up time HPWH efficiency at low DHW usage is lower than expected Basement wall insulation in humid climates substantially reduces mold and dehumidification load Even in net zero situations, a lot is imported from the grid Net zero performance is no substitute for superinsulation

43 More detail? For more detailed information, please see my blog: And my web site:

44 Thank You! Marc Rosenbaum, P.E. South Mountain Company West Tisbury, MA