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

THE BASICS: THE “X” FLOW

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

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

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

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

Heat Recovery Ventilators Energy Recovery Ventilators 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 cross-leakage) 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 moisture-handling 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

VS INSTALLATION GUIDELINES – ELBOWS Long-Radius Elbows Image Source: http://isystemsweb.thomasnet.com/item/duct-and-components/machine-made-elbows/elmm11-45?&seo=110&bc=100%7C1015

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.

Excess length should not be stored in a bag Coiled EQUIVALENT LENGTH MULTIPLIERS1 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 The recommended standard of care is 4% or less coil compression and negligible sag (2.5 inches sag per 5 feet of span). 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). Compression occurs when excess length is squeezed into a shorter straight line span (see Table A17-3, next page). It is possible to have excess length with negligible compression. 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. The equivalent length of compressed duct equals the product of the measured span length and a compression-sag multiplier. These equivalent length values do not apply any to other type of duct material. 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. 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 A17-2

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 MANUFACTURER/BRAND MODEL TYPE CFM EFFICIENCY (LOW SPEED) WATTS ANNUAL FAN ENERGY USE JE Stork Air WHR 950 / CA 350 HRV 101 84% 69 604 Am Aldes 200 SRD 63 70% 87 762 Broan/Nutone Guardian HRV 200H 109 69% 92 806 Bryant HRVBBLVU1200-A 111 158 1384 ERVBBLHU1200-A ERV 110 93 815 Lennox HRV2-195DDP 114 77% 116 1016 Lifebreath 200 MAX 300DCS 119 150 1314 Renewaire EV200 181 78% 157 1375 Rheem/Ruud 84-HRV-200 Ultimate Air RecoupAerator 200DX 83% 73 639 Trent Metals Ltd. Summeraire SHRV185ST 117 68% 999 Venmar HRV5585 Compact 964 AVS HRV EKO 1.5 81 73% 32 280 155 ECM 98 63% 74 648

HIGHER EFFICIENCY = HIGHER DELIVERED TEMPERATURES

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 24hr/day x 365 days/year = 3504 KWh/year Could be up to 3000 kWh a year in energy use; that’s $300 @ .10cents/kWh 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?

BALANCING POTENTIAL PROBLEMS FOR AIR HANDLER CONNECTED SYSTEMS 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 WPN 11-6 mandated implementation of ASHRAE 62.2 into the WAP by January, 2012. The directive was modified by WPN 11-6a to delay full implementation until Program Year 2012. ASHRAE produces standards by consensus. ASHRAE 62.2 was originally promulgated in 2003, first revised in 2007 and then again in 2010. It is both a performance and a prescriptive standard, in that the actual fan-delivered CFM must be verified by flow testing after installation rather than simply reading the design CFM off the fan unit label. 62.2 considers chemical, physical and biological contaminants but not thermal comfort. Following 62.2 does not guarantee that good IAQ will be achieved! (but it will show that you followed the rules if you ever land in court over an IAQ issue!) So what will this new standard mean to your program? A 2004 Wisconsin pilot study found that it increased the percentage of homes needing additional mechanical ventilation, from 47% with ASHRAE 62.1 to 78% with 62.2. But the size of the fans required was smaller – down from 60 CFM under 62-1989 to 30 CFM under 62.2. They found that for homes requiring ventilation under the 62.2 standard, the average cost for the fan, controls, and installation was around $525 (2004-2005 prices). 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 4.1a (I-P)

ROOM AIRFLOWS Supply to bedrooms and main body 10 cfm per person 10 cfm small bedroom 20 cfm master bedroom 20 cfm main body Exhaust from bathrooms, kitchen (not near the stove) 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 DEFROST LOGIC: Logic changes between systems Temp only Change in efficiency How long does it last?

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

IN COLD CLIMATES

THE FIFTH PORT: ALLOWS FOR VENTILATION DURING RECIRCULATION

IN LINE DUCT HEATERS ARE NOT DEFROST SYSTEMS

DEFROST TIMES FOR LIFEBREATH 195 -3 C° (27F°) 3 minutes of defrost, 25 minutes of HRV -20 C° (-4F°) 4.5 minutes of defrost 17 minutes of HRV -35 C° (31F°) 7 minutes of defrost  14 minutes of HRV

IN LINE DUCT HEATER CONTROLS: WHAT COULD GO WRONG?

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

BALANCING Aldes, iaq source supply

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: Exhaust > than supply = negative building pressures Supply > than exhaust = positive building pressures

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

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

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

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

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

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

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

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

WHAT COULD GO WRONG?

Thank You!