National energy savings potential in HUD-code housing from thermal envelope and HVAC equipment improvements

ASHRAE Transactions, July, 2007 by Robert Lucas, Philip Fairey, Robert Garcia, Michael Lubliner

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Table 3 reproduces the national average results shown in Figure 4. This table provides the energy cost savings over the worst case, the current HUD-code. The savings are shown both with and without the improved heating and cooling equipment efficiencies. The first three columns of results are at the standard, or low, efficiency level from Table 2. The final column accounts for both the improved codes/programs and the improvement in HVAC efficiency.

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Table 3. National Average Energy Costs by Heating System Type

                      Heating,    Cooling,  Total,       Savings
                         $           $        $         Over HUD,
                                                            $

                                                      Without    With
                                                     Improved   Improved
                                                        HVAC     HVAC

Electric    HUD         814       229    1043           --        25
resistance

            NFPA        702       213     915          128       152

            IECC        636       187     823          220       241

            ENERGY      638       179     817          226       246
            STAR

            Best        474       150     624          419       435
            Practice

Natural     HUD         466       234     700           --        75
gas

            NFPA        402       221     623           77       143

            IECC        368       198     566          134       194

            ENERGY      366       191     557          143       203
            STAR

            Best        270       165     435          265       312
            Practice

Heat pump   HUD         428       228     656           --        61

            NFPA        366       212     578           78       132

            IECC        337       187     524          132       181

            ENERGY      335       178     513          143       190
            STAR

            Best        252       149     401          255       293
            Practice

Table 4 shows the same results but using source energy, not energy cost. Source energy takes into account the impact of power plant and distribution system efficiency by multiplying the energy used by 3.2 for electric and by 1.02 for gas (DOE 2006c; DOE 1995).

Table 4. National Average Source Energy Use by Heating System Type

                      Heating,  Cooling,  Total,   Savings
                        MBtu      MBtu     MBtu   Over HUD,
                                                    MBtu

                                                   Without     With
                                                  Improved   Improved
                                                    HVAC       HVAC

Electric    HUD             96        25     121         --         2
resistance

            NFPA            83        24     107         14        17

            IECC            75        21      96         25        27

            ENERGY          75        20      95         26        28
            STAR

            Best            56        17      73         48        50
            Practice

Natural     HUD             44        26      70         --         8
gas

            NFPA            38        25      63          7        14

            IECC            35        22      57         13        19

            ENERGY          34        21      55         15        20
            STAR

            Best            25        18      43         27        32
            Practice

Heat pump   HUD             51        25      76         --         7

            NFPA            43        24      67          9        15

            IECC            40        21      61         15        21

            ENERGY          40        20      60         16        22
            STAR

            Best            30        17      47         29        34
            Practice