VENTILATION BEST PRACTICES FOR ERVS AND HRVS Northwest

VENTILATION BEST PRACTICES FOR ERVS AND HRVS Northwest ENERGY STAR Homes Program| September 2013

THE BASICS: THE “X” FLOW

THE SINGLE MOST IMPORTANT INSTALLATION DETAIL Make sure exhausts exhaust and intakes intake

PORT Location STALE AIR FROM INSIDE FRESH AIR FROM OUTSIDE FRESH AIR TO INSIDE STALE AIR TO OUTSIDE Inside Outside

WHERE DATA LIVES HVI TESTED/CERTIFIED Heat Recovery Ventilators and Energy Recovery Ventilators (HRV/ERV) (DUCTED HEAT AND ENERGY RECOVERY VENTILATORS)

IS A HRV OR ERV LATENT RECOVERY/MOISTURE TRANSFER (LRMT): Moisture recovered divided by moisture exhausted and corrected for the effects of cross-leakage. LRMT = 0 indicates that moisture was not transferred (net of crossleakage) from the exhaust airstream to the supply airstream. LRMT = 1 would indicate complete transfer of moisture. LRMT is provided for the Heating Season Performance and the Very Low Temperature Test as an indication of moisturehandling characteristics, and it may be used to evaluate the moisture transfer ability of the equipment in order to assess the humidification or dehumidification performance of the product at the specified test condition.

DEFINITIONS NET SUPPLY AIRFLOW The gross supply airflow reduced by measured cross-leakage (EATR). This is the actual amount of outside air supplied by the unit and is used only for sizing the equipment for the required ventilation rate. Use this rating for ventilation sizing

AIRFLOW IS NOT A GIVEN

FAN CURVES

STATIC PRESSURE DROP AND READINGS

FLEX LIKE YOU HAVE NEVER SEEN Avoid bending ducts across sharp corners or incidental contact with metal fixtures, pipes or conduits. Radius at center line shall not be less than one duct diameter.

FLEX LIKE YOU HAVE NEVER SEEN

INSTALLATION GUIDELINES – ELBOWS Long-Radius Elbows VS Image Source: http: //isystemsweb. thomasnet. com/item/duct-and-components/machine-made-elbows/elmm 11 -45? &seo=110&bc=100%7 C 1015

INSTALLATION GUIDELINES – ELBOWS Account for bends and offsets in the flexible duct. A 90 -degree bend has a pressure drop equal to approximately twenty (20) lineal feet of flexible duct. So each 90 -degree bend will add twenty (20) equivalent feet to the length used for sizing calculations. A gradual 45 -degree bend has a pressure drop equal to about ten (10) lineal feet of flexible duct. A 180 -degree offset has a pressure drop equal to about forty (40) lineal feet of flexible duct.

EQUIVALENT LENGTH MULTIPLIERS 1 FOR WIRE HELIX DUCT WITH COMPRESSION AND SAG Compression Superimposed Sag Negligible 1 -inch/Ft 2 -inch/Ft 0% to 4% 1. 0 1. 1 15% 2. 0 2. 2 30% 3. 4 3. 7 45% 5. 2 5. 7 Bagged Excess length should not be stored in a bag Coiled Excess length should not be coiled 1. The recommended standard of care is 4% or less coil compression and negligible sag (2. 5 inches sag per 5 feet of span). 2. These multipliers apply to airway sizing tools (friction chart or slide rule) that model the performance of duct that has less than 4% excess length and negligible sag (test stand condition). 3. Compression occurs when excess length is squeezed into a shorter straight line span (see Table A 17 -3, next page). It is possible to have excess length with negligible compression. 4. The measured span length of flexible duct is the straight line length from entrance to exit (no Group 11 turns), from entrance from a Group 11 turn to the exit. 5. The equivalent length of compressed duct equals the product of the measured span length and a compression-sag multiplier. 6. These equivalent length values do not apply any to other type of duct material. 7. Airway sizes for wire helix duct are read from the Manual D wire helix friction chart, or equivalent; or use the wire helix scale on the ACCA Duct Sizing Slide Rule, or equivalent. 8. Duct fiction charts vary from product to product (depending on construction details). The friction chart or duct slide rule provided by the manufacturer of a particular flexible duct product supersedes the Manual D friction chart and the ACCA Slide Rule. Table A 17 -2

OTHER DUCTING OPTIONS

MORE DEFINITIONS APPARENT SENSIBLE EFFECTIVENESS (ASE) The measured temperature rise of the supply air stream divided by the difference between the supply temperature (and exhaust temperature) and multiplied by the ratio of mass flow rate of the supply divided by the minimum of the mass flow rate of the supply or exhaust streams. This value is useful principally to predict final delivered air temperature at a given flow rate. The efficiency not including the electrical energy used by the system

MORE DEFINITIONS SENSIBLE RECOVERY EFFICIENCY (SRE) The sensible energy recovered minus the supply fan energy and preheat coil energy, divided by the sensible energy exhausted plus the exhaust fan energy. This calculation corrects for the effects of cross-leakage, purchased energy for fan and controls, as well as defrost systems. This value is used principally to predict and compare energy performance. The efficiency including the energy use of the system

WHY EFFICIENCY MATTERS Yes, it lowers energy use. But it also increases the delivered air temperature. This means less air conditioning and higher air-delivered air temperatures.

WHY EFFICIENCY MATTERS

CHECK WATTAGE OF HRV / ERV EFFICIENCY WATTS ANNUAL FAN (LOW SPEED) ENERGY USE MANUFACTURER/BRAND MODEL TYPE CFM JE Stork Air WHR 950 / CA 350 HRV 101 84% 69 604 Am Aldes 200 SRD HRV 63 70% 87 762 Broan/Nutone Guardian HRV 200 H HRV 109 69% 92 806 Bryant HRVBBLVU 1200 -A HRV 111 84% 158 1384 Bryant ERVBBLHU 1200 -A ERV 110 69% 93 815 Lennox HRV 2 -195 DDP HRV 114 77% 116 1016 Lifebreath 200 MAX HRV 63 70% 87 762 Lifebreath 300 DCS HRV 119 77% 150 1314 Renewaire EV 200 ERV 181 78% 157 1375 Rheem/Ruud 84 -HRV-200 HRV 109 70% 92 806 Ultimate Air Recoup. Aerator 200 DX ERV 101 83% 73 639 Trent Metals Ltd. Summeraire SHRV 185 ST HRV 117 68% 114 999 Venmar HRV 5585 Compact HRV 119 77% 110 964 Venmar AVS HRV EKO 1. 5 HRV 81 73% 32 280 Lifebreath 155 ECM HRV 98 63% 74 648

HIGHER EFFICIENCY = HIGHER DELIVERED TEMPERATURES Delivered Air Temp at Various OATs and ASEs 75 70 Delivered Air Temp 65 60 55 50 45 40 35 30 65 70 75 80 85 Apparent Sensible Efficiency 60 F 40 F 90 95

OPTIONS FOR INSTALLATION

STAND-ALONE SYSTEMS

STALE AIR FROM HOUSE, FRESH AIR TO RETURN

STALE AIR FROM RETURN, SUPPLY AIR TO RETURN

STALE AIR FROM RETURN, FRESH AIR TO SUPPLY

DETAIL FOR INTRODUCING FRESH AIR INTO A SUPPLY DUCT

POTENTIAL PROBLEMS FOR AIR HANDLER CONNECTED SYSTEMS INCREASED ENERGY USE § To avoid cross-commination of air streams, the furnace fan should run whenever the DHP is in exchanging air: 400 watts x 24 hr/day x 365 days/year = 3504 KWh/year o Could be up to 3000 k. Wh a year in energy use; that’s $300 @. 10 cents/k. Wh o That’s ignoring any extra duct losses if the duct are outside

POTENTIAL PROBLEMS FOR AIR HANDLER CONNECTED SYSTEMS OVERCOMING LARGE NEGATIVE AND POSITIVE PRESSURES IN THE RETURN AND SUPPLY § Do the pressures generated by big furnace fan ever overpower the pressure generated by the small ERV/HRV fan?

POTENTIAL PROBLEMS FOR AIR HANDLER CONNECTED SYSTEMS BALANCING § With an increase of multi-staged or modulating equipment that have ECMs, what fan speed do you balance at? § How do you know what fan speed you’re at? § As filters and coils get dirty the pressures in the duct change

NOISE: KEEP IT QUIET, STUPID

SEPARATE EXHAUST FROM INTAKE

ASHRAE 62. 2 -2010 www. ashrae. org

BASIC FORMULA FOR CONTINUOUS VENTILATION RATE Required CFM for continuous ventilation § CFM =. 01 x Floor area + 7. 5 x (#bedrooms + 1) Example: § 2500 square foot house with 2 bedrooms § . 01 x 2500 + 7. 5 x (2 + 1) = 25 + 22. 5 = 47. 5 cfm

VENTILATION AIR REQUIREMENTS, CFM Based on: ASHRAE 62. 2, Table 4. 1 a (I-P)

ROOM AIRFLOWS § Supply to bedrooms and main body 10 cfm person o 10 cfm small bedroom o 20 cfm master bedroom o 20 cfm main body § Exhaust from bathrooms, kitchen (not near the stove) o ASHRAE 62. 2 allows 20 cfm continuous instead of 50 cfm bath fan (save some money)

DON’T USE WALL HOODS WITH GRAVITY DAMPERS AS FRESH AIR INTAKES

SETTING THE CONTROLS Controls need to be up to meet ASHRAE 62. 2

DEFROST OPTIONS § Recirculation of indoor-air: No ventilation when this occurs! § Exhaust only, no heat recovery § Electric heating element § Geothermal or pumped glycol loop

DEFROST LOGIC: § Logic changes between systems o Temp only o Change in efficiency o How long does it last?

GEO THERMAL BOOSTER Can help heat the air in winter and cool air in summer; also works as defrost 45

IN COLD CLIMATES 46

THE FIFTH PORT: ALLOWS FOR VENTILATION DURING RECIRCULATION 47

IN LINE DUCT HEATERS ARE NOT DEFROST SYSTEMS 48

DEFROST TIMES FOR LIFEBREATH 195 § -3 C° (27 F°) 3 minutes of defrost, 25 minutes of HRV § -20 C° (-4 F°) 4. 5 minutes of defrost 17 minutes of HRV § -35 C° (31 F°) 7 minutes of defrost 14 minutes of HRV 49

IN LINE DUCT HEATER CONTROLS: WHAT COULD GO WRONG? 50

OTHER TYPES OF HRVS Lunas reversing heat recovery HRVs Panasonic Spot ERN 51

BALANCING Aldes, iaq source supply 52

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BALANCING: WHY IT’S IMPORTANT § Efficiency: The rated efficiency is given at specific set of conditions. If unbalanced, the rated efficiency is not known. § Building pressure: o Exhaust > than supply = negative building pressures o Supply > than exhaust = positive building pressures 54

BEST PRACTICES: SYSTEM SELECTION § § High apparent sensible efficiency will produce higher delivered air temperatures High sensible recovery efficiency will produce the lowest energy use 55

BEST PRACTICES: LOCATION OF UNIT § § Easily accessible Inside the conditioned space Venmar 56

BEST PRACTICES: DISTRIBUTION § § Stand-alone is the best Stale from house, fresh air to return side of air handler o AH static pressures work with HRV/ERN not against o AH and HRV/ERV do not have to be tied together o When AH is off fresh air will enter into the duct work, some might exit the return, but who cares? 57

BEST PRACTICES: DUCT WORK § § § Size using a low friction rate (. 06) or manufacturer’s recommendation Keep inside the condition space Don’t do stupid stuff with flex duct Minimize duct length through central location Use mastic, seal air them airtight 58

BEST PRACTICES: WALL HOODS § § Maintain separation of exhaust and intake units hoods Don’t use gravity dampers on intakes Place where the homeowner can clean them Caulk insect screen in place if it has gaps between screen hood and the hood Venmar 59

BEST PRACTICES: COMMISSIONING § § § Balance as per manufacturer’s recommendation Measure airflow per room Double that intakes intake and exhausts exhaust Set controller to meet AHRAE 62. 2 Record all reading and post on unit 60

BEST PRACTICES: COMMISSIONING § § Compare temperatures between incoming and outgoing air. Does it match efficiency rating? Aldes 61

BEST PRACTICES: HOMEOWNER EDUCATION § § § Leave all manuals, especially ones concerning setting the controller Emphasize filter and screen cleaning Document all testing and commissioning Sell a maintenance contract Emphasize the importance of ventilation 62

WHAT COULD GO WRONG? 63

THANK YOU!