Regular HVAC Maintenance

Over time, the efficiency of electric air conditioners and heat pumps degrades due to dirty coils, refrigerant charge drift, fouled filters, and worn components. A professional tune-up restores much of this lost performance. This measure quantifies the energy and demand savings from servicing electric-powered cooling and heat pump equipment that has not received a tune-up in the previous three years. It applies to central A/C systems and heat pumps of 20 tons or less, and requires each unit's rated capacity, efficiency ratings, and equivalent full-load hours.

ARC Code(s):

2.7211 (Clean and Maintain Refrigerant, Condensers, and Cooling Towers)

Savings Calculation

Savings are driven by the improvement factor, which expresses the fractional efficiency gain a tune-up delivers. It is applied to the unit's annual cooling (and, for heat pumps, heating) energy use.

\[ F_{\text{improv}} = \frac{\eta_{\text{post}} - \eta_{\text{baseline}}}{\eta_{\text{post}}} \]

where:

$F_{\text{improv}}$ = fractional improvement from the tune-up (unitless)
$\eta_{\text{post}}$ = post-tune-up efficiency rating — SEER, SEER2, IEER, EER, or HSPF as applicable
$\eta_{\text{baseline}}$ = baseline (pre-tune-up) efficiency rating in the same metric

Default improvement factor when ratings are unknown

When pre- and post-tune-up ratings cannot be measured, build $F_{\text{improv}}$ from NJ TRM Table 3-178 by summing the percent savings for each maintenance component performed:

Maintenance component	% savings
Condenser cleaning	6.10
Evaporator cleaning	0.22
Refrigerant charge offset ≤ 20%	0.68
Refrigerant charge offset > 20%	8.44

Typically, we'll assume the first three rows of this table apply if the unit has not had a tune-up in the previous 2 years.

Annual Energy Savings

Total electric savings combine the cooling component (all units) and the heating component (heat pumps only):

\[ \Delta \text{kWh} = \Delta \text{kWh}_{\text{cool}} + \Delta \text{kWh}_{\text{heat}} \]

\[ \Delta \text{kWh}_{\text{cool}} = \text{CAP}_{\text{cool}} \times \text{EFLH}_{\text{cool}} \times \frac{1}{\eta_{\text{cool,baseline}}} \times F_{\text{improv}} \]

\[ \Delta \text{kWh}_{\text{heat}} = \text{CAP}_{\text{heat}} \times \text{EFLH}_{\text{heat}} \times \frac{1}{\text{HSPF}_{\text{baseline}}} \times F_{\text{improv}} \]

where:

$\Delta \text{kWh}_{\text{cool}}$ = annual cooling energy savings (kWh/yr)
$\Delta \text{kWh}_{\text{heat}}$ = annual heating energy savings, heat pumps only (kWh/yr)
$\text{CAP}_{\text{cool}}$, $\text{CAP}_{\text{heat}}$ = rated cooling and heating capacity (kBTU/hr)
$\text{EFLH}_{\text{cool}}$, $\text{EFLH}_{\text{heat}}$ = equivalent full-load cooling and heating hours (hrs/yr)
$\eta_{\text{cool,baseline}}$ = baseline cooling efficiency rating — SEER, SEER2, or IEER, whichever matches the unit's nameplate (use IEER for rooftop units rated above 65,000 BTU/hr)
$\text{HSPF}_{\text{baseline}}$ = baseline heating efficiency rating

Choosing the cooling efficiency metric

Use the metric the unit is actually rated in, and keep $\eta_{\text{post}}$ and $\eta_{\text{baseline}}$ in that same metric. SEER and SEER2 are reported for smaller, single-phase equipment; larger commercial rooftop units (RTUs) rated above 65,000 BTU/hr are rated by IEER (or EER), so prefer IEER for those. Do not mix metrics — a SEER baseline against an IEER post-tune-up rating will produce a meaningless improvement factor.

Peak Demand Savings

The cooling load drives the summer peak, so demand savings — for both air conditioners and heat pumps — use the cooling capacity, the baseline EER, and the electric coincidence factor:

\[ \Delta \text{kW}_{\text{summer}} = \frac{1}{\text{EER}_{\text{baseline}}} \times F_{\text{improv}} \times \text{CF} \times \text{CAP}_{\text{cool}} \]

where $\text{EER}_{\text{baseline}}$ is the baseline cooling efficiency rating and $\text{CF} = 0.478$ is the electric coincidence factor. Because the demand reduction is driven by cooling, no winter peak demand is claimed ($\Delta \text{kW}_{\text{winter}} = 0$).

\[ \Delta \text{kW-months} = (\Delta \text{kW}_{\text{summer}} \times 3) + (\Delta \text{kW}_{\text{winter}} \times 9) \]

Annual Cost Savings

\[ \text{Annual Savings} = (\Delta \text{kWh} \times R_c) + (\Delta \text{kW-months} \times R_d) \]

where:

$R_c$ = facility consumption rate ($/kWh)
$R_d$ = facility demand rate ($/kW-month)

Anticipated Costs

The exact cost of a tune-up is difficult to determine without quotes from local contractors, so use the allowance method for an estimate. Multiply the appropriate per-unit allowance by the number of units serviced:

Unit size	Mounting	Allowance
5 tons or more	Ground-mounted	$175 / unit
5 tons or more	Rooftop	$225 / unit
Less than 5 tons	Any	$125 / unit