HomeMy WebLinkAbout1115 Aruba Dr - Disclosures - 07/23/2001I)IL:5 kf12n-Pr--
23 July 2001
TO: Whom it may concern
FROM: Jim Evenson, ENERGY SCORE rater, phone (970) 484-3531, fax (970) 490-2925 ;
RE: City of Ft Collins Energy Code compliance ;
James Company 2401 Plan, UPDATED AND CORRECTED, supersedes 14 July letter
t
James Company submitted these plans to the rater for use via the systems analysis method of complyg with the
Fort Collins Energy Code requirements. It is a two-story over 95% basement and 5% crawl space. It s an
unusually large (compared to the average home) ratio of window glazing to floor space of 16.7%! Partly this is
because it has six egress windows in the basement and partly because it has large windows, some of which also have
transoms. It has 3785 square feet for Energy Score and Energy Code purposes. Crawl space was treated by rater as
heated space, which added to volume of house slightly (360 cubic feet) without adding to floor square footage. On
the other hand this eliminated heat ducts through unheated space and more reflects the reality rater has experienced
on other models by the builder. The square footage requires at rating of G-83 to comply with the Energy Code.
Specifications used by rater:
R-38 ceiling insulation, no cathedral ceilings.
R-15 Rim and Band joist insulation at exterior joists with R-19 in the 24 foot crawl area.
R-15 fiberglass batt insulation in exterior wall insulation in 2 x 4 exterior walls, OSB sheathing at corners for
structural with, fiberbrace (credit of net R-.8) on the rest.
Foundation insulation: R-I I on unfinislied basement walls, R-19 on crawl space walls.
Windows: Double pane vinyl, NOT low-E.
R-30 insulation in the cantilever floor (6 square feet over entry).
No ceiling insulation in normal crawl space (perimeter is insulated)
Air infiltration figure of .4 air changes per hour OR LESS. (Note: this is lower than usually used for from plans
ratings but rater has done blower door tests on this builders other homes and thinks it reasonable)
Furnace efficiency (rated by GAMA) of 90%.
No duct insulation on ducts going through normal height crawl spaces (area heated per rater assumption).
57% efficient (as rated by GAMA) hot water heater or better.
These specifications produced an Energy Score of G-83 for this property. This G-83 rating passes the above
mentioned Energy Code requirement of G-83 for a home this size, but just barely. Rater had to "upgrade" builder's
typical specifications in order to reach this rating. Builder is cautioned to check efficiency of furnace and water
heater with rater (who will consult his GAMA data relative to efficiency) before installation in order to avoid the
situation where an installed appliance does not have the required efficiency. Also see paragraph below.
This rating is done from plans. It is subject to site inspections by the City during construction and the final
inspection (including blower door test to determine infiltration) when the home is complete. The inspections will
include not only to make sure the specified materials were used but also that installation of the materials met the
City standards as published in a number of locations, including the City of Fort Collins Builder's Guide to Energy
Efficient Home Construction, and also available on-line at www.ci.fort-colllins.co.us. While your use of the
analysis methods (results based) means you can let the performance count rather than meeting many of the specific
standards mentioned, you must meet the standards such as: 1) ductwork must meet Uniform Mechanical Code
requirement; 2) water heater tank must have either a) heat traps or b) minimum of one inch of pipe insulation for the
first eight feet of both hot and cold water pipes from it; 3) combustion air requirements must be met; and 4)
disclosure forms for insulation and mechanical systems must be provided.
This plan had other options, i.e. a 3-car side load garage rather than 3-car tandem. The 3-car side load has less
shared wall between garage and home and would need to be separately rated as the heat load would be different.
Another option is a walk out basement or at least a garden level. Since this option involves foundation level frame
walls (at R-15 rather than R-11 basement walls) and less glazing, that option, by itself, should rate higher than the
subject's options list and probably does not need a separate rating. Please call me with any questions or comments.