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Knowledgebase : RdSAP Conventions (E&W) Iss.8
RdSAP is for assessment of existing dwellings only. Where an EPC is required for a new dwelling under building regulations it must be a SAP EPC. Any new dwelling, including dwellings created by change of use, must be assessed using SAP. For this purpose a...
A dwelling that does not extend to all storeys of the building is a flat or maisonette. RdSAP makes no distinction between flats and maisonettes as regards calculations; it is acceptable to select either type as definitions vary across the UK.
Assessors must ensure that the correct country is identified so that the EPC will be lodged in the appropriate register.
A property can have a physically separate building or 'annex' which if self-contained needs to have its own EPC. If not self-contained but contains rooms that are used as part of the main dwelling, e.g. bedrooms, study etc in a large detached garage or ...
State on site plans whether the dimensions recorded are external or internal. Where a combination of external and internal is used this must be made clear for each dimension indicated. When measuring internally, measure between the finished internal sur...
Measure to one decimal place (0.1 m) or better. Retain higher precision when that has been measured (especially room heights).
Include in the heat loss perimeter. When a dwelling (flat or maisonette) has a sheltered wall to an unheated corridor on more than one storey the sheltered length is the total for all storeys with a sheltered wall (example: 2 storeys with sheltered wall...
Habitable rooms include any living room, sitting room, dining room, kitchen/diner, bedroom, study and similar; and also a non-separated conservatory. Excluded from the room count are: any room used solely as a kitchen, utility room, bathroom, cloakroom,...
Include when accessed via a permanent fixed staircase such that one is able to walk downwards facing forwards and either:- - basement is heated via fixed heat emitters, or - basement is open to the rest of the dwelling, i.e. no door. Does not necessaril...
Include when accessed via a permanent fixed staircase such that one is able to walk downwards facing forwards. Does not necessarily contain habitable rooms. For a roof room to be classed as such and not a separate storey, the height of the common wall m...
A storey having non-vertical walls of at least 70° pitch constitutes a separate storey; it is not treated as roof rooms. Use alternative wall if appropriate.
When the property or a building part of it is a single storey entirely located within a roof, model as: - lowest occupied level - timber frame construction of appropriate age band - room height must be entered as 2.2 m - include area and perimeter measure...
If heated always include (separated or not). If external and not heated, disregard. If internal, not heated and thermally separated, disregard.
Enter the part of the property above and below the mezzanine deck as a two storey extension. Treat the remaining part as a single level with the full floor to ceiling/roof height. If the mezzanine is located such that it has no heat loss perimeter then ...
Where an extension has been built over part of the existing dwelling, divide the part built over into two, one of which has "same dwelling above" and for the other describe the roof construction and insulation. Enter the new upper floor as an extension ...
Add together floor areas and exposed perimeters of extensions (or add extension to main dwelling) to reduce to four extensions. Combine parts having the most similar age bands (refer to SAP Appendix S for U-values of relevant constructions). Use alternati...
In determining whether an alternative wall is applicable the significant features are construction type, dry lining, age band, insulation and whether sheltered by unheated corridor. A sheltered wall between the dwelling and an unheated corridor or stair...
In RdSAP the definition of what is a window and what is a door is defined by the area of glazing in relation to the area of the whole opening, i.e. door and frame. To be classed as a window a glazed door and frame must contain glazing amounting to 60% or ...
Consider the whole dwelling (windows, glazed doors and roof lights), including any extensions (BUT NOT CONSERVATORIES). TYPICAL applies if the surface area of the glazing in the dwelling is essentially as would be expected of a typical property of that ...
If single glazing with secondary glazing, record as secondary glazing. If double glazing with secondary glazing, record as newer double glazing (newer double glazing means 2002 or later in E&W, 2003 or later in Scotland, 2006 or later in N. Ireland). ...
For a highly glazed part of the dwelling, such as a sun room, which does not meet the criteria for a conservatory (50% of walls and 75% of roof glazed), in most cases use the glazing option of "more than typical". That adds 25% to the total glazed area of...
Do not mix internal and external measurements. If a basement is included in the assessment, it is likely that internal dimensions will be used throughout the dwelling.
If heated always include. If accessible only via a separate external door and not heated, disregard. If directly accessible, not heated and thermally separated, disregard.
If heated from main heating system, always include. The presence of a boiler within the garage does not make it heated.
If a dwelling or part of a dwelling has commercial premises below record as partially heated space below. If a dwelling or part of a dwelling has commercial premises above record as another dwelling above. If a dwelling has commercial premises alongsi...
Measure wall thickness in mm of each external wall (elevation) and any alternative wall within a building part. Photographic evidence is required for each different thickness. It can be measured at door or window reveals or by internal/external measurem...
Where an individual wall (elevation) is not heat loss for its full height (because of stepped arrangements either within the dwelling or between the dwelling and an adjacent one) obtain the "effective heat loss perimeter" for the individual wall as follow...
To be recorded in all cases (except detached properties). A flat in a block having ONLY an unheated corridor adjacent to it is treated as detached (no party wall).
Where a cavity wall has been identified, enter as such irrespective of the width of the cavity
If there is a system built wall that has evidence of retro cavity fill, record as system build with internal insulation and include Addendum 1. See also convention 3.14 relating to high rise. Timber frame should be recorded as such and not as system b...
Assume as-built if there is no evidence of retro-fitted insulation, including: 1. a pitched roof with sloping ceiling insulation or a flat roof where there is no documentary evidence. 2. a roof with rafter insulation if no evidence of retro-fitted ins...
This convention refers unknown insulation, not unknown insulation thickness. Do not use the "unknown" option for insulation inappropriately as this automatically suppresses any insulation recommendation. "Unknown" should be used only in exceptional ci...
Where the loft is accessible, loft insulation should be measured and photographic evidence provided of its measured thickness. "No access" means there is no loft hatch or other means of gaining access to the loft space. If there is a loft hatch or oth...
For a conversion which was a change of use (e.g. barn converted to a dwelling) or where a dwelling has been sub-divided (e.g. house to flats) use the original construction date, unless there is documentary evidence that all thermal elements have been upgr...
This includes any type of internal lining that creates an airspace behind it, e.g. plasterboard on dabs, lath and plaster. Use tap test for plaster board on dabs or on battens. If tap test is inconclusive regard as not dry-lined. Note. Applies only to s...
If insulation is multifoil or foam insulation the thickness is entered as double the actual thickness. This is the same convention as for insulation at joists. If there is both internal and external wall insulation add the insulation thicknesses togethe...
The U-value is that of the whole element, including any added insulation. Documentary evidence applicable to the property being assessed (see convention 9.02) must be provided and recorded if overwriting any default U-value. This evidence shall be either:...
An external door is a door that forms part of the heat loss perimeter of the dwelling. See 2.14 for treatment of highly glazed doors. A multiple door should be recorded as such, e.g. a double door should be counted as 2 doors. A door to a heated acces...
U-values and g-values can be overwritten only if documentary evidence is provided, which can be either a Window Energy Rating certificate (as defined by BFRC) or manufacturer's data. The U-value is for whole window, not centre pane.
In this convention window refers only to openable panes. All external doors and at least 2 windows per building part should be examined. If a window is locked or inaccessible then endeavour to check another one. If the state of the draught proofing ...
For double glazed windows, the year of manufacture can often be found either on the spacer bar at the edge of the glazed unit, or the year is stamped into the frame. Choose unknown date if there is no evidence of the date (on spacer bar or frame or docu...
Same as the building part unless evidence proves otherwise.
High rise properties (greater than 4 storeys) built with non-traditional construction methods (i.e. not timber frame, solid brick, cavity brick, stone) are deemed to be system built and should be recorded as such. For high rise properties built during o...
This is the width of the spacer bar between the two panes of glass. It is required for windows with PVC frames pre 2002 or unknown. Select the nearest value to 6, 12 or 16 mm. If the gap cannot easily be identified, select either 6 or 16. Where a mixtur...
The essential party wall characteristic to identify is masonry construction with a cavity which could be filled. Solid masonry and other constructional types are classified as "solid masonry or timber frame or system built". The primary method of identi...
If one heating system feeds both underfloor and radiators, enter radiators. This is because for radiators a higher flow temperature is assumed (unless flow temperature is known). Where known the design flow temperature should be entered for condensing b...
If storage heaters are present as main heating but there is only a single rate meter - enter as panel heaters and include addendum 6. If the storage heaters are fan-assisted or high heat retention suppress the recommendation for high heat retention storag...
If boiler/heating system is present but not working (or condemned) it should still be entered as the main heating system. If boiler not present but intended - enter no heating system.
If micro-CHP and the system cannot be found in the database enter as condensing boiler and include addendum 5.
A system in which a heat generator provides heat and/or hot water to more than one premises. Each dwelling to be assessed individually. If the heat generator is in the dwelling, it is the heating system for that dwelling. If the heat generator is no...
Where the community scheme can be identified in the community network database, it is to be selected. If there is more than one data record only the current record can be used. Otherwise try to find out what the fuel is. If it cannot be ascertained sele...
There is an option for two main systems to cover the situation of different systems heating different parts of the dwelling. If main system 1 heats all habitable rooms, there is no main system 2 unless it serves DHW only (see 6.04). Main systems 1 and...
Used only for appliances selected from the database
Applies only if documentary evidence confirms that the property receives LPG at mains gas prices.
For straw bales and other types of biomass fuel that are not available in RdSAP, select wood logs and include addendum 12.
Include when on 50% or more of the radiators (all radiators, not just those in habitable rooms).
Treat as electric panel heaters.
An electric CPSU uses 10-hour or 18-hour tariff. If on 7-hour tariff treat as water storage boiler. If on single tariff record as direct-acting electric boiler.
Include only if located in database.
a. separate plumbing circuits, either with their own programmer, or separate channels in the same programmer, or b. programmable TRVs or communicating TRVs that are able to provide time and temperature zone control (conventional TRVs without a timing fu...
Separate pump only, not within boiler. Record age as unknown if cannot be seen (including pumps within the boiler). Age is 2013 or later if it has a label stating the EEI (energy efficiency index); otherwise it is 2012 or earlier.
Include if fixed emitter present regardless of whether main system(s) heat all rooms. If more than one secondary: select the device that heats greatest number of habitable rooms. If the same choose cheapest fuel - if same fuel select the device with t...
An open fireplace is to be considered in the heating assessment if capable of supporting an open fire (that includes having a grate suitable for holding fuel), even if no fuel is present. The fuel to be specified is smokeless fuel in smoke control areas a...
If it can burn only one fuel, specify that fuel (includes exempted appliances burning wood in Smoke Control Areas). Otherwise: Smoke control area: Open fire - smokeless fuel; closed heater - anthracite Not smoke control area: Open fire - dual fuel; cl...
Enter as a single immersion and include addendum 6.
Sometimes there is a separate boiler or heat pump providing DHW only. A generic boiler can be selected from the water heating options. If the boilers or heat pumps are located in the database, specify two main heating systems with: - main system 1 is the ...
For an unvented pressurised steel or plastic encased hot-water cylinder (e.g. Megaflo), treat insulation value as 50 mm factory-applied foam and assume cylinderstat is present. For Elson (wooden box) type record the actual thickness and check for the pres...
Include only when mounted on the side of the cylinder and has an electric connection.
LEDs are considered as low energy lights. Where there are 4 or more downlighters / ceiling lights divide the bulb count by 2. Include fixed under-cupboard kitchen strip lights. If no lamp is present: do not treat as a low energy outlet unless it can...
Recommendations should be removed only if there is documentary evidence showing that a specific recommendation is not appropriate. A listed building or a property in a conservation area is not sufficient grounds in its own right to suppress a recommendati...
Only if a gas meter or a gas burning appliance (e.g. gas cooker) is within the property. A closed-off gas pipe does not count. Where a boiler is present attached to a heating system (not in a box), and the mains gas meter has been removed for security r...
Include all open chimneys/fireplaces in the fireplace count (both downstairs and upstairs). The definition is a vertical duct with a flue diameter of at least 200 mm or its equivalent. The following are not counted as open fireplaces: * Any open flue th...
Acceptable documentary evidence includes official letters from the applicable Registered Social Landlord (RSL) or certificates, warranties, guarantees, building control sign-off, from anybody else, including RSLs. The assessor must be confident, and able ...
If you lodge an EPC in error and lodge a corrected EPC, inform your accreditation scheme so that the erroneous one can be marked "not for issue".
Fixed systems only, do not include reversible heat pumps.
If photovoltaics are present, look for a schematic wiring diagram which may be adjacent to the electricity meter or the consumer unit or an MCS installation certificate, either of which should state the peak power (kWp) of the PV array. Record the followi...
Include only if found in database, identified in same way as for heating systems. When the model cannot be found no default option is available but the presence of the device should be recorded in site notes.
Documentary evidence is required to overwrite default values.
Include only if found in database. When the model cannot be found no default option is available but the presence of the device should be recorded in site notes. For instantaneous types: - Number of rooms with bath and/or shower includes rooms with on...
Documentary evidence is required to over-write collector or solar store values. Orientation, tilt and overshading can be overwritten with visual evidence. If the panel/collector details are available but the solar store information is not, the default v...
An access issue is any façade where it is not possible to pitch a 5 metre ladder considering health and safety requirements. This includes e.g. a narrow passageway, a busy thoroughfare a building of more than 2 storeys, a conservatory or large outhouse at...
If more than one transaction type is applicable, seek clarification from the client and in case of doubt select the one nearest the top of the list.
When transaction type is rental, tenure must be rented (social) or rented (private). When transaction type is marketed or non-marketed sale, the tenure will usually be owner-occupied (although there can be exceptions, such as the sale of a property with...
Usually the dwelling uses either the standard domestic tariff (single meter) or an off-peak tariff (dual meter). In these cases select single or dual meter and an addendum is not required. In some cases of older installations the property may have two s...
For the purposes of RdSAP a park home is a pre-fabricated dwelling of modular lightweight construction without its own foundations (although it may sit upon a concrete base) and which is capable of being moved from one place to another. Convention 3.08 ...