Report Number

FSEC-CR-1983-14

URL

http://publications.energyresearch.ucf.edu/wp-content/uploads/2018/06/FSEC-CR-1983-14.pdf

Keywords

Buildings; Affordable housing; Energy efficiency; Solar energy; Home Energy Rating System; Cost-effectiveness

Abstract

The Building America Partnership for Improved Residential Construction (BA-PIRC) worked with two affordable housing builders who pursued and achieved CH certification. Both builders needed very few changes to reach CH; however, both were already certifying homes under the ENERGY STAR® for Homes Standard v.3.1. Habitat for Humanity affiliates’ mortgage terms are 0% interest over a 30-year mortgage to qualified buyers. To improve relevance of the study to the general homebuilding community, the cost-effectiveness calculations herein are based on a code-minimum reference rather than the builders’ standard practice (ENERGY STAR), and projected first year cash flow is provided for both the builders’ actual finance terms and for a market rate of 7% for the same mortgage period. MCHFH pursued CH in duplex dwellings built with insulated concrete forms, an unvented attic, a ducted mini-split variable-capacity heat pump, a solar water heater, and a photovoltaic (PV) array. SEVHFH pursued CH in a frame home with a vented attic (regional convention), a seasonal energy efficiency ratio (SEER) 15 heat pump, and an innovative modified truss configuration that created an interior duct chase. The latter was featured in a Building America case study. The MCHFH and SEVHFH CHs scored 53 and 49, respectively, on the Home Energy Rating System (HERS) Index. With the addition of a 2.5-kW PV array, the HERS Index score dropped to 23 for the CH built by MCHFH. Using the actual finance terms (0%, 30 years), cost analysis shows that MCHFH’s CH costs $17,008 more than an identical geometry code-compliant home: $9,234 for solar hot water and PV and $7,774 for the rest of the improvement package. The projected first year cash flow associated with these two packages was $36 and $382, respectively, based on EnergyGauge USA calculations. This includes revenue generated from the sale of electricity back to the utility in the amount of $427 annually. MCHFH received renewable energy utility incentives available only to affordable housing providers that improved first year cash flow to $690. Based on cost data provided by SEVHFH and data collected in previous studies, researchers estimate the cost of SEVHFH’s CH with renewable-ready compliance (with a heat pump water heater) to be $4,636 compared to code-minimum specifications. This was reduced by a $600 in-kind donation available to all Habitat for Humanity affiliates from Dow Corporation. An additional $4,700 cost was incurred for a solar water heater, which was partially offset by the cost avoided for the heat pump water heater. Using the actual finance terms (0%, 30 years), the projected first year cash flow associated with these two packages was $214 and $238, respectively, based on EnergyGauge USA calculations. SEVHFH received a similar utility rebate for affordable housing for the full cost of the solar water heater that improved projected first year cash flow to $395. Using market-rate finance terms (7%, 30 years), the projected first year cash flow is negative for both the renewable-ready and the solar-equipped scenarios for both houses. These calculations do not necessarily reflect the economics achievable by market-rate builders. The improvement packages were developed for a specific builder’s resources which, in this case, included large utility incentives with limited availability. Market-rate builders may benefit from economies of scale or in-house labor capabilities that would implicate a different improvement package. A preliminary analysis, conducted with a certified home energy rater, should be used to evaluate the projected energy savings and cost effectiveness of various improvements that suit a particular builder. Several gaps and barriers to broader CH standard adoption were identified, including need for refinement of the innovative modified truss approach to interior duct systems developed by SEVHFH, research documenting the pros and cons associated with meeting the American Society of Heating, Refrigerating and Air-Conditioning Engineers Standard 62.2 ventilation rates, and a survey of stakeholders to develop a menu of ventilation strategies in use in the hot humid climate region. The survey could help researchers identify which approaches are of greatest interest to stakeholders—those gaining market share, which are favored, and why.

Date Published

8-29-2014

Identifiers

168

Subjects

Low-income housing; Energy conservation; Solar energy; Cost effectiveness

Local Subjects

Buildings

Type

Text; Document

Collection

FSEC Energy Research Center® Collection

Download

Share

COinS
 

Rights Statement

In Copyright