Good afternoon all,
We are in the process of modeling an hotel type building, and we are reviewing if we can claim savings due to reductions in lighting power in the guest rooms or if we need to treat these spaces as neutral for lighting power purposes (as in a dwelling unit).
As we understand it, the spaces that are out of the scope of section 9, are dwelling units, which a hotel guestroom should not fall into since it is not a permanent residence, and therefore all section 9.4 mandatories regarding lighting apply; however when reviewing how to model the proposed and baseline LPDs for these spaces, there is table G3.1.6.d which basically says that all lighting needs to be counted, but it has an exception:
Exception: For multifamily dwelling units, hotel/motel guest rooms, and other
spaces in which lighting systems are connected via receptacles and are not
shown or provided for on building plans, assume identical lighting power for
the proposed and baseline building designs in the simulations
And that land us in a situation where we can have a few different scenarios:
- If we have a guest room with both lighting fixtures and lamps, with known power, should we use the total lighting power for the proposed LPD (adding hardwire and receptacle lighting) and the baseline would be 1.11 W/SF per table 9.6.1? This means the baseline model would include the receptacle lighting in the 1.1 W/SF.
- If we have the guestroom with only the lighting fixture known (the hardwired lighting), but the lamp's power is unknown. Should we assume a lighting power for the lamps, consider this lamp power a process load, and therefore model the same in proposed and baseline, but for the LPD of the room use only the proposed lighting fixture power and compared that to the 1.11 W/SF? Or should we model both baseline and proposed in a neutral way with the same LPD, and model (or not) the lighting via receptacle as a process load in both models?
Thank you,
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
September 15, 2022 - 2:53 pm
The reason why plug in lighting fixtures should be modeled identically is that the bulbs can easily be changed to a higher wattage. I would use your option 1 for all the hard wired fixtures and your option 2 for all the plug in lighting fixtures making sure that the total baseline is no more than 1.1 W/sf.
Camilo Velez
PrincipalSimgea
21 thumbs up
September 15, 2022 - 4:42 pm
Hi Marcus, thank you for your response. So to make sure that I'm understanding correctly:
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
September 15, 2022 - 5:12 pm
Technically I suppose that plug in lighting is plug load which is process but in a hotel room it is often the primary lighting source for the room. So I would include it in the total LPD not as a part of the plug load. While I think you could probably get away with #2 by the letter of the law it does not seem right and would overstate the lighting savings.
The baseline is 1.11 W/sf. The Proposed would be as designed. For the hardwired fixtures I would assume a resonable wattage bulb or if it is know use that value. Again techically you should be using the labeled maximum wattage of the fixture (see Section 9.1.4).
Hotel rooms are not the same as multi-family residential since they are a regulated space type so no need for the photometric report.
Camilo Velez
PrincipalSimgea
21 thumbs up
September 15, 2022 - 6:35 pm
I agree with you Marcus, I think that this is the reasonable approach then, include all the lighting (hardwired and receptacle) into the proposed LPD calculation and compare it against the baseline LPD of 1.11 W/SF.
Thank you