| 9.36.4. |
Service Water Heating Systems |
| 9.36.4.1. |
Scope and Application
- This Subsection is concerned with the efficient use of energy by systems used to heat service water for household use as well as for indoor pools and hot tubs.
- Where service water heating equipment or techniques other than those described in this Subsection are used, the building shall be designed and constructed in accordance with the energy efficiency requirements of the NECB.
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| 9.36.4.2. |
Equipment Efficiency
- Service water heaters, boilers, pool heaters and storage tanks shall comply with the performance requirements stated in Table 9.36.4.2. (See Note A-9.36.4.2.(1).)
- Hot service water storage tanks not listed in Table 9.36.4.2. shall be covered with insulation having a minimum thermal resistance of 1.8 (m2·K)/W.
Table 9.36.4.2.
Service Water Heating Equipment Performance Standards
Forming Part of Sentences 9.36.4.2.(1) and (2)
Notes to Table 9.36.4.2.:
(1) 1 kW = 3412 Btu/h
(2) The symbols and abbreviations used in this column have the following meanings:
EF = energy factor, in %/h
Et = thermal efficiency with 38.9°C water temperature difference
OTPF = overall thermal performance factor
S = standby loss, in %/h (percentage heat content of stored water per hour)
SL = standby loss, in W
TPF = thermal performance factor
V = storage volume, in L, as specified by the manufacturer
Vm = measured storage volume, in US gallons
(3) Includes propane.
(4) Rated input is measured in watts.
(5) Consistent with the U.S. Congress "National Appliance Energy Conservation Act of 1987."
(6) No standard addresses the performance efficiency of electric tankless service water heaters; however, their efficiency typically approaches 100%.
- Except for components that are required to be installed outdoors, service water heating equipment shall be installed in a conditioned space. (See Note A-9.36.4.2.(3).)
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| 9.36.4.3. |
Solar Domestic Hot Water Systems
- Service water heating systems that use solar thermal technology shall conform to the manufacturer's design requirements and installation procedures.
- Service water heating systems that use solar thermal technology shall be installed in accordance with the NPC.
- Hot water storage tanks associated with the systems referred to in Sentence (2) shall be installed in a conditioned space.
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| 9.36.4.4. |
Piping
- The first 2 m of outlet piping downstream and of inlet piping upstream leading from a storage tank or heating vessel shall be covered with piping insulation that is at least 12 mm thick.
- All piping forming part of a continuously operating recirculating service water heating system shall be covered with piping insulation that is at least 12 mm thick.
- Where piping forming part of the service water heating system is located outside the building envelope or in an unconditioned space, it shall be insulated to a thermal resistance not less than the effective thermal resistance required for the exterior above-ground walls.
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| 9.36.4.5. |
Controls
- Service water heating systems with storage tanks shall be equipped with automatic temperature controls capable of adjustment between the minimum and maximum temperature settings permitted for the intended use.
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| 9.36.4.6. |
Indoor Swimming Pool Equipment Controls
- Heaters for indoor swimming pools shall be equipped with
- a thermostat, and
- a readily accessible and clearly labeled device that allows the heater to be shut off without adjusting the thermostat setting.
- Pumps and heaters for indoor swimming pools shall be equipped with time switches or other types of controls that can be set to automatically turn off the pumps and heaters when their operation is not required. (See Note A-9.36.4.6.(2).)
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