"Here's a very recent article on Green Building Advisor that reinforces the issues to…"
BPI's October Stump the Chump!
The following stumper is presented in BPI's October Performance Matters e-Newsletter.
This month's stumper comes from a chump who's actually stumped! Ed Revers of Michell Timperman Ritz Architects in New Albany, Indiana has been scratching his head about this one and is wondering if you can help.
Ed explains that he has been working on a 50 year old house that has a four ton top-of-the-line Florida Heat pump system, with all the energy saving bells and whistles (hot water de-super heater, four-zone stats on Arzel control board, etc). After 2 years of utility bills, the energy savings are nowhere near what the geothermal manufacturers claim they should be. The new energy bills (gas and electric combined) are the same as the past 20 years, during which an old forced-air conventional gas furnace was used. The mechanical contractor has come out several times to check things and reports that it is working fine. The house was super-insulated when the new geothermal system was made operational. It isn't easy to compare old to new systems equally, because an addition of about 25 percent was added to the house when the new system was installed.
Background: The house is in the Louisville, Kentucky area and is now a 2850 sq. ft. ranch with a basement. Mechanical installation costs exceeded $30K, with four grouted wells at 150' depth each. At the recommendation of the mechanical contractor, the house was zoned because the existing house limited duct work configuration options and R-values weren't equal everywhere. The new system performs well (70 in the summer and 68 in the winter), but the energy savings are disappointing. The weather has actually been pretty mild the past few years too. As a newly accredited BPI Building Analyst, Ed considers the house to be tight and well insulated; although no blower door test or duct efficiency test has been performed to verify this. Gas and electric usage is probably below average for a family of four. Any clue as to what would help lower the utility bills and make the system less expensive to operate?
Tags: BPI, Chump, Contest, Matters, Newsletter, Performance, Stump, the
Views: 156
Replies to This Discussion
-
Permalink Reply by tedkidd on -
Be really helpful to see the load calc and have a blower door #.
The new system performs well (70 in the summer and 68 in the winter)
A 70 setting for comfort in summer indicates gross oversizing. (poor latent removal means lower sensible is required to achieve comfort.) From there you can suspect cycling losses/short cycling is partially to blame for lack of efficiency.
They didn't expect to save on heating when they have natural gas, did they? Exaggerated expectations by the sales person, and acceptance without research by the homeowner, can also be partially to blame.
Are they tracking entering and leaving water temperatures? Run times? How about External Static Pressure? These things will better tell how much of a design failure we have than "it maintains the temperature we set it at".
-
-
Permalink Reply by David Berg on -
looking at the information provided:
1 - is the system a multistage unit to better match load as well as zoning demands.2 - is the heating capacity properly matched to to home demand - does the backup heat run?
3 - is the cooling capacity too large - so homeowner sets thermostat lower to dehumidify
-
-
Permalink Reply by James White on
-
When you say, "The new energy bills are the same as the past 20 years", my first response would be to show me the data so I can run a billing anlysis. I put together a spreadsheet that analyzes gas and electric billing histories. The analysis simply calculates the average energy usage for each bill and plots it with that month's average monthly temperature. This normalizes the data for different number of read days in each month and adjusts for weather variations.
-
Home Energy Pros
Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy, under the American Recovery and Reinvestment Act) and brought to you in partnership with Home Energy magazine.
Latest Activity
David Eakin commented on Elisa Wood's blog post Momentum builds for energy efficiency...but is the wolf at the door?
Egr renovation posted a status"of course he is in paris but works around europe
http://ning.it/16KrbS7"
Egr renovation posted a status"i just find a good photogrpahe for your master piece
http://www.armanimage.com"
Meagan Foster posted eventsHomes 401: Green Rater Training
August 15, 2013 to August 16, 2013BPI Building Analyst Field Training
September 9, 2013 to September 12, 2013BPI Building Analyst Field Training
July 15, 2013 to July 18, 2013
Meagan Foster updated an eventEnergyLogic's RaterFest! at Black Hawk, CO
September 13, 2013 at 10am to September 15, 2013 at 12pm
Join us for one of the best home energy conferences available! This retreat will provide…See More
Meagan Foster updated an eventHomes 401: Green Rater Training at Berthoud, CO
June 25, 2013 to June 26, 2013
This highly interactive workshop builds upon the material presented in the online course, further…See More
Meagan Foster updated an eventHERS Rater Training - Online at Online
July 1, 2013 to July 26, 2013
NEW - our great RESNET HERS Rater online training is now completely self-paced, so you can start at…See More
Meagan Foster updated an eventBPI Building Analyst Training - Online at Online
June 3, 2013 to June 28, 2013
Join the EnergyLogic Academy for our BPI BA online training - we just went to a completely open…See More
© 2013 Created by Lawrence Berkeley National Laboratory.
