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energy efficiency specs

posted by: energy_rater_la on 01.23.2013 at 03:07 pm in Building a Home Forum

this is a short version of the spec sheet I give my
clients for building an energy efficient home.

lots of posts about lots of things here, but
over and over I read about things that could
easily have been dealt with in planning & early
construction phases of the build.
hopefully, this will help to bring some of these
to light now in the decision making phase of
your build.

things that don't 'show' are important choices.
efficiency costs are always upfront & savings long term.

Summary of Energy Efficiency Specifications

Air Infiltration Goal is .25 Natural Air Changes per Hour�heating. Gaskets such as Owens-Corning FoamSeal R or Dow Sill Seal between sole plate and slab is recommended. For 2nd story or bonus rooms, insulate and seal openings between floor joists, under walls with foam board sheathing material. Seal all windows and doors jambs with minimal or non expanding foam.

Seal all wire penetrations especially those through top plate.
Incorporate Airtight Drywall Approach throughout home. Run sheetrock all the way to bottom plate behind showers and tubs, seal plumbing penetrations under tubs especially on upper floors.

Minimize use of recessed lights or install Insulation Contact Air Tight (ICAT) lights. Existing recessed lights that are not air tight can be retrofitted with air tight trim kits. Get name brand and model numbers of lights to order trim kits.

Windows Double-glazed with Low-E glass and non-heat-conducting frames are recommended. Look for U-values and SHGC (solar heat gain coefficient) of less than .3 for best performance in this area. Go to www.nfrc.org to learn more about window types and labels on windows.

DOORS Steel, polyurethane foam core (R 2.5 to 5.0) with high quality weather-strip. Solid wood door with double-glazing allowed for front door. Exterior-type foam-core doors with good air seals on doors to all attic spaces and knee-walls.

Walls 2x4 walls R-15 un-faced insulation with double sided 1" foil sheathing boards. 2x6 walls R-19 also with double sided foil sheathing boards.

Face unprinted side to exterior. Sheathing must cover top plate to sole plate. Seal all seams with foil tape. Use �" foil sheathing in between 2X headers instead of plywood. Insulate behind tub and shower units before installing units.

Ceilings R-30 minimum with a Radiant Barriers are recommended for this climate. Visit Florida Solar Energy Center�s web site for more information on radiant barriers www.fsec.ucf.org

Seal and insulate attic accesses when in the conditioned areas. If attic staircase s in conditioned area, seal with attic tent or build a box with 2x12 with �" plywood for top, insulate and weather-strip to seal well.

Unvented attics Open cell foam. foam must meet R-value
code requirements. No quanitive values accepted.
foam must fill rafter bays and faces of rafters.
Foam must seal from roof to attic floor to create true
unvented attic. Full inches to be installed, not
'average' fill. No areas with 1/2" of foam to 9" of
foam to be averaged for overall R-value. Unvented
attic with foam is a semi conditioned attic.

Use only closed cell foam in floors for homes
on piers. install minimum of 3"

Use Energy efficient (O.V.E.) framing at corners and partition walls, See LaDNR Builder�s Guide To Energy Efficient Homes in Louisiana or Doug Rye video.

Continuous ridge vents ( with wind baffles) and continuous soffits vents. One square foot of net free area for every 150-sq.ft. of attic floor space, divided equally between ridge and soffits vents.

NO ATTIC POWER VENTS !!!

Duct Leakage and Insulation Duct loss must be no more than 5%. Before insulating hard pipe seal all joints & seams. Use Mastic or an approved UL-181 rated mastic tape, such as Hardcast #1402 mastic tape.

Have HVAC contractor size A/C system using Manual J. Design duct layout using Manual D.
Upgrade insulation values from a standard R-4.2 to R-6 or R-8 is recommended.

Water Heaters Compare Energy Factors (E.F.) Gas E.F. of .65 on a standard tank and E.F. of .95 on an electric standard tank.

Adding an insulating blanket can also increase the efficiency of water heaters.

Instant, tankless gas water heaters have higher E.F. of .85.
Electric tankless water heaters are not efficient.
instead look at standard hign EF electric tanks
The most efficient for electric Heat Pump water heaters (also called heat recovery or desuperheaters) provide 90% to 100% free hot water in summer months.

Cooling 14 SEER, 0.75or less Sensible heat fraction (SHF) mandatory minimum requirement. 15 to 17SEER is recommended.
Heat pump if all electric.

Two speed or variable speed system if over-sizing of tonnage.
Consider Zoned system versus multiple units.
700 sq. ft. per ton as opposed to old
rule-of-thumb of 400 to 500 sq. ft. per ton.

Bigger is not better!

Heating Gas furnace AFUE 80% minimum.
Efficiency on these units up to 94% (condensing unit with PVC flue).
For Heat Pumps specify a minimum of HSPF of 8.0. Variable speed heat pumps will have up to 9.0 HSPF.
(May change to higher AFUE with IRC code changes)

Lighting Use fluorescent lighting whenever possible. Compact Fluorescent in all fixtures like recessed lights.

IC Air Tight recessed lights are mandatory requirements. Existing recessed lights can be retrofitted with air tight trim kits available at lighting stores and box outlets.

Appliances Purchase Energy Star Appliances for high efficiency, especially refrigerators, freezers and water heaters which run 24/7.
Look for Energy Guide labels in the lower range for more efficiency.

Additional Links:
La. Energy & Environmental Resource Building Science Corporation
www.laeeric.lsu.edu/energy www.buildingscience.com
LSU Ag Center Hot Humid Climates
www.lsuagcenter.com Builder�s Guide
Energy Star Program www.eeba.org
www.energystar.gov

NOTES:

Energy efficiency
clipped on: 06.18.2014 at 03:58 pm    last updated on: 06.18.2014 at 04:01 pm

RE: LED recessed cans guide for kitchen ... (Follow-Up #2)

posted by: davidtay on 01.30.2012 at 12:39 pm in Lighting Forum

For your situation, it would probably look more symmetrical if the lights are centered on the aisle and there are no other sources of light for general lighting.

On the other hand, a counter argument can be made that as there probably will be pendants over the island, the cans should be placed around the edge of the countertop.

There is a LED Continuation thread that covers strip lighting. Puck spacing really depends on the output of each puck and the length of cord between. Installing puck lighting could be more work than the equivalent strip light since each would have to be individually fastened and aligned along with the cord between.

Island pendants can take many shapes from a suspended tube light to individual lamps (40W / 60W/ ...).

LED bulb tips
1. Always look for the output in lumens. Never rely on vague claims of "output like X watts" which is an old trick.
2. If the output per watt is ~ 20+ per watt, that is no better than using a halogen. The L-prize bulb from Philips produces > 90 lumens per watt.
3. The CRI should be 80 or better.

Here is a link that might be useful: LED UCL continuation

NOTES:

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clipped on: 12.23.2013 at 10:12 am    last updated on: 12.23.2013 at 10:12 am

LED recessed cans guide for kitchen ...

posted by: davidtay on 01.30.2012 at 01:27 am in Lighting Forum

A collection of tips/ answers
Since kitchens have higher lighting requirements, I like to use 35 lumen per sq ft as a rule to compute the number of lights. If there are additional sources of light that will be used, the output (lumens not watts) from those sources can be deducted from the total.

Placement/ layout
1. Cans should be > 24 to 30 inches from the wall (on center). Most countertop spaces have upper cabinets (typically ~ 12" deep) + crown molding. The edge of the can may be spaced ~ 12" away from the edge of the crown molding (if present or cabinet if there is no crown molding) making the average distance between 26 to 30 inches.

2. Assuming the need for a fairly uniformly lit space @ 35 lumens per sq ft, the cans may have to be spaced closer together - between 3 - 4 ft apart (if all general lighting is provided by recessed lights). A fairly regular pattern is preferable to a random layout.

3. The actual layout of cans will be impacted by the location of ceiling joists, HVAC ducting, electrical wiring, plumbing, ceiling height, fire suppression sprinklers and other obstructions above the ceiling.

Dimming
The Cree LR6 series lamps do not dim as well as the later models (CR6, ...). ELV dimmers probably work better with LR6 than incandescent dimmers since the total load of the lights may not meet the minimum load requirement for the incandescent dimmer.

Dimmers such as the Lutron Diva CL dimmers work well. The max output is 95%.

Some Choices (in order of preference) and notes
Cree CR6 or ECO-575 (Home Depot branded CR6)
ECO4-575 (Home Depot branded Cree CR4 4" recessed light)
The above are only available in 2700k light color.

Cree LR6 series - including the LE6.

The Cree CR6 and LR6 lamps will not fit into 5" housings.

The standard LR6 behaves more like a surface mount than a recessed light as the LED emitters are close to the surface and the recess is shallow. Some may not like the amount of light spillage (standard LR6).

There is a higher output version of the LR6 that has a much deeper recess.

To prevent the Cree lamps from falling out, the 3 prongs have to be fully extended and a slight clockwise twist made when push installing. The slight clockwise twist will ensure that the prongs are fully extended.

The Cree lamps are currently the best available today (2012).

Sylvania RT-6, RT-4. The lights could be easier to install than Cree lamps as they utilize the torsion spring mechanism. However, the lights do not look as pleasant as the Cree lamps.

The Cree and Sylvania lamps do outperform 26W CFLs (and incandescents) in a standard recessed can in terms of light spread and output as the standard bulb in a can solution traps a significant amount of light. The Cree and Sylvania recessed lamp solutions referenced above have all the LED elements facing outwards so that the effective light output is higher.

The CRI (Color Rendition Index) of Cree and Sylvania recessed lamps > 80.

There is no warm up time required for Cree recessed lamps, unlike CFL light bulbs.

Most recessed lighting is used with flat ceilings. Sloped ceilings would require special solutions such as the LE6 or some other form of lighting (i.e. -non recessed lighting).

Some common objections to recessed can lights stem from
1. looks and performance of traditional can lights (standard bulb in a can)
2. swiss cheese effect from too many holes.

NOTES:

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clipped on: 12.23.2013 at 10:10 am    last updated on: 12.23.2013 at 10:11 am