It is a legal requirement to secure a BER certificate for a new dwelling, before it is sold or occupied for the first time. When performing a BER assessment, this dwelling is treated as a new dwelling in DEAP. As stated in DEAP, the methodology applies to existing dwellings and is not appropriate for new dwellings.
Default values that are applicable for both new and existing dwellings are available in other sections of the DEAP Manual. For example, the default values for heating system seasonal efficiency available in Table 4.4 can be applied to both existing and new dwellings, if appropriate evidence or HARP entry is not available to support the use of a non-default efficiency. Similarly, defaults from Table 2.28 apply to windows for both new and existing dwellings.
The guidance in this note refers to exceptional cases where there is insufficient evidence available to use non-default data in New-Final BER assessments, and there are no applicable defaults in DEAP. These occurrences would be exceptions, as in the vast majority of cases documentary evidence must be available as part of the as-built sign-off1.
BER Assessors are expected to make reasonable efforts to obtain as-built details for the new dwelling where these are not available from the survey. Defaults must only be relied upon when there is insufficient supporting evidence to use non-defaults. BER Assessors must keep a record detailing the reasons why defaults had to be used. This will help provide clarity if the assessment is audited by SEAI.
The guidance in the following sections helps BER Assessors on how to deal with such exceptions. If BER Assessors are still in doubt, they should contact the Helpdesk for advice.
BER Assessors need to highlight with their clients the importance of providing sufficient supporting evidence to allow the use of more accurate performance data in the calculations. Using the defaults in the following guidance is likely to result in a failure of the TGD L conformance check. BER Assessors should inform their clients in advance of BER publication that this aspect may impact compliance with Part L of the Second Schedule of the Building Regulations.
1 See Code of Practice for Inspecting and Certifying Buildings and Works, available from the NCBO Website
Where specifications of some fabric elements are not available (see examples below), the assumption in DEAP is that if the element does not have insulation specified or confirmed by sign-off, there is lower confidence on the level of insulation installed for that element. It is expected that this will only occur for small/isolated sections, and for larger areas only in very exceptional or extenuating circumstances. In this case, the defaults to be applied are as follows:
Table 3: U value defaults applicable to New Final
|
Building element |
U Value [W/m²K] |
|
Roof (any type) |
0.22 |
|
Wall |
0.27 |
|
Floor |
0.25 |
|
Door |
3 |
In cases where a specification provides the full make-up of the element, but the precise type and manufacturer of insulation is not specified, then a thermal conductivity from table 4 below can be used.
Where sufficient data is not available to identify the type of insulation installed, a thermal conductivity of 0.044 W/mK can be used in the U-value calculation for that element.
Table 4: Thermal Conductivity values
|
Insulation Material |
Thermal conductivity (λ) W/mK |
|
Expanded polystyrene (EPS) slab (HD) |
0.044 |
|
Expanded polystyrene (EPS) slab (SD) |
|
|
Extruded polystyrene |
|
|
Mineral fibre / wool quilt |
|
|
Mineral fibre / wool batt |
|
|
Cellulosic insulation |
|
|
Phenolic foam (rigid) |
0.028 |
|
Polyurethane board (unfaced) |
|
|
Polyurethane foam |
|
|
Polyisocyanate |
|
|
Polyisocyanurate board |
|
|
Polystyrene beads |
In cases where certified data is not available for windows or doors, the appropriate defaults from table 6a should be selected. When details for use of table 2.28 are not available, the following assumptions should be made:
Table 5: Default data for windows
| Frame Material | Type of glazing | U-Value | Solar Transmittance |
| Wood/PVC/Aluclad | Double-glazing | 2.0 | 0.72 |
| Wood/PVC/Aluclad | Triple-glazing | 1.5 | 0.64 |
| Metal | Double-glazing | 2.5 | 0.72 |
| Metal | Triple-glazing | 1.9 | 0.64 |
Important note: BER Assessors should inform their clients of processes relating to the lack of documentary evidence as early as possible when they become aware of potential issues.
| Issue | Action | |
| Example 1 | No specifications sign-off is available for a small, exposed floor over a ground floor recessed porch with no sign off . | Assign a U value of 0.25 W/m2K to the exposed floor over the porch. |
| Example 2 | With a split level floor, there is no confirmation on the makeup of the wall between the upper and lower level. | Assign a U value of 0.27 W/m2K to the portion of external wall between upper and lower level. |
| Example 3 | No confirmation on the makeup of timber walls of a dormer. | Assign a U value of 0.27 W/m2K to the walls of the dormer |
| Example 4 | No confirmation on the makeup of the roof of a dormer. | Assign a U value of 0.22 W/m2K to the roof of the dormer |
| Example 5 | No acceptable evidence of the U value of a front door can be sourced from the client. | Assign a U value of 3 W/m2K to the door |
| Example 6 | As built sign-off of a wall or roof confirms the address, thickness, and type of insulation material, but is missing the product name and no additional information can be retrieved by the BER Assessor. | Apply the relevant default thermal conductivity from table 4 above in the U value calculations for the wall/roof. |
| Example 7 | The certificate for the sidelight of an entrance door is missing. | The appropriate defaults from table 2.28 or from Table 5 above should be selected. |
| Example 8 | No certificate or acceptable calculations are provided for a flat roof glazing system. | The appropriate defaults from table 2.28 or from Table 5 above should be selected. |
For New Final BERs, BER Assessors should apply the assumptions from the following table when the required data or information cannot be sourced during the survey or from acceptable as-built documentary evidence.
| Parameter | Data entry assumptions if unknown from survey or evidence |
| Showers and baths |
Assume the option resulting in highest overall primary energy usage in DEAP. Default shower type: Vented with pump (highest flow rate) |
| Instantaneous wastewater heat recovery |
If the instantaneous WWHR system is not listed on the PCDB, do not include the WWHR in the DEAP assessment. Default for this entry is none present |
| Is water usage target 125L/person/day? | Default is No |
| Flow rate and flow restrictors |
DEAP assumes defaults for shower flow rate if unknown. By default, assume flow restrictors are not present, unless proven otherwise. |
| Insulation of primary pipework | By default, assume primary pipework is not insulated, unless proven otherwise. |
| Storage Vessel heat losses |
Storage vessels placed on the market since 26th September 2017 are required to be Ecodesign compliant, therefore if an Assessor is reasonably confident that the cylinder in the dwelling was installed after 2017, then the formula below can be used to calculate a default standing loss for entry in DEAP. (16.66 + 8.33 * V0.4) * 0.024 kWh/day. Where V is the volume of the vessel in litres. |
| Space heating circulation pump for wet systems | Within heated space may be assumed (in the unlikely case that the pump cannot be located during the site survey) |
| Hot water separately timed / separate temperature control | Default is Yes (in the unlikely case that this information cannot be sourced during the site survey) |
| Solar collector |
If solar collectors are present, the following data can be used for any unavailable parameters: · total aperture area of all collectors = 3 m² · ŋ0 and/or a1 from Table 5.9 · facing south, pitch 30°, modest overshading · combined cylinder, dedicated solar part one-third of total, or if a combi boiler the cylinder identified is a dedicated solar cylinder. · pump is not solar powered. |
| Photovoltaics |
• A default area of 1.5 m² per panel may be used where the area cannot be measured or estimated reliably from roof measurements. • The 2016 onwards default of 0.120 kWp/m² can be assumed. |
| Group heating scheme |
If details cannot be ascertained, they are defaulted to: • For locations on the gas grid: system based on mains gas-fired boiler, efficiency 83%, • For locations not on the gas grid: system based on oil-fired boiler, efficiency 83%, Group heating scheme • Modern pre-insulated piping system operating at 100ºC or below, full control system installed in 1991 or later, variable flow system If CHP and details cannot be ascertained they are defaulted to: • Fraction of heat from CHP = 0.30, • CHP overall efficiency 75%, • Heat to power ratio = 2.0. |
| Cooling Seasonal Efficiency (SEER) | Seasonal Energy Efficiency Ratio (SEER) is assumed to be 2.5. |