Easy RSS are the UK's No.1 provider of Renewable Design Software primarily for the renewables and microgeneration sector. Easy RSS specialise in supporting Renewable Installers and MCS Installers all over the UK in compliance with the design and calculation requirements under MCS Certification and for technologies under the Renewable Heat Incentive and Feed in Tariffs.

The Solar PV design area will allow you to carry out performance estimations of all sizes under the standard method stated in the PV Guide. 

Yes, you have the ability to allow for up to 4 strings in the same calculation. 

A compass will provide you with a direction from 0° to 360°. A Solar PV system works best facing as close to due south as possible.

If you have estimated the heat loss for both power and energy and know what flow temperature you wish to use you can skip room by room heat loss calculation and go straight to the design calculations for your chosen technology. 

This will determine what U-Values will be selected for the external wall elements within the heat loss section. 

More modern homes have reduced their levels of ventilation which reduces heat loss and improves energy efficiency. 

An exposed location will mean a property that has no surroundings, or possibly on a hill or close to the sea. When completing heat loss calculations you allow for the design to cope with outside air temperatures affecting the building. 

Intermittent heat is a system that is designed to be on for less than 16 hours per day. For systems on for more than 16 hours per day, this would be classed as continuous heating. 

Thermal bridging occurs when there are gaps between materials and structural surfaces causing “cold spots”. This can have an effect on the heat loss of a building. Within the software you can make an allowance for thermal bridging on individual elements such as external wall when calculating your heat loss. 

A Cob house is a property built out of naturally resources such as earth and soil instead of bricks or timber.

The reason for this is due to slight difference in calculation between them both including the Degree Days. 

The difference within the Air Change factor is for any properties that were built pre-2007 then the standard value you use is 0.33. 

Yes, you have the ability within the specific room information page to input the room volume as a manual input. 

There is always the option to select the “custom” for the fabric type which will allow you to manually input any U-Value you wish. 

A Party Wall is the wall that separates the property you are working on to a neighbouring property. 

You will need to refer to your radiator manufacturer’s catalogue to ensure that the Output at the mean Water to Air Temperature in Watts at 50°C (MW-AT 50°C) is big enough for the design temperature in question.

When using Underfloor Heating (UFH) you would select from the underfloor options that ties in with your chosen installation. When adding a new inventory item, you would put in the description the type of pipe and the pipe spacing distance too.

The correction factor is applied to all heat emitters apart from underfloor heating based on the flow temperature of the heating system. 

Yes, the software allows for any auxiliary heat sources for both heating and hot water. 

This figure will be the size of the heat source (kW) required based on your design hot water flow temperature and any design conditions which may have an effect. 

It is an MCS requirement that there will be a prevention for bacterial growth such as legionella. This is due to the low temperatures associated with heat pumps and solar thermal and it is at these temperatures where bacteria can grow within the system. 

The SPF for Hot Water means the Seasonal Performance Factor of the Heat Pump in Hot Water mode. 

The reason for this is due to “tank in tank” cylinders are generally more insulated than normal cylinders and therefore would set these to 85%. 

The hot water storage cylinder must be large enough to provide for a household’s peak hot water demand, but more water will be heated than needed if the cylinder is too large. The appropriate size depends primarily on the number of people in the household. 

The nominated technical person for each technology should be the person carrying out the calculations. If a non-technical person is using the software, then the technical representative should be available to ensure the correct data is being entered.

You will need to enter the postcode on the project information section, this will pre-populate the design conditions on the right hand side of the project information page. This will pin point your exact location including the altitude and average ground & outside design temperature for heat pumps and biomass installations. 

It is important that any RHI payback given to the customer is based only on a valid EPC. The software will provide you with an RHI payment based on calculations, however, this is only to be used as a very rough guide. 

The software is mobile and Ipad friendly, however there would need to be an internet connection to be able to access the software. 

The Solar Thermal section is very manufacturer specific, and therefore you would need to gather the test report for the Solar Collector known as the EN12975 Test Report. On there you will find all the information to enter into the software.

Of course, your consultant is always on hand to answer questions and assist in completing your projects. We also hold regular FREE webinars which will go through each aspect of the software in detail including a full question and answer session. 


Below are some Frequently Asked Questions on the Solar PV area of the Easy RSS Design Software.

Below are some Frequently Asked Questions on the Heat Loss area of the Easy RSS Design Software.

Below are some Frequently Asked Questions on the Domestic Hot Water area of the Easy RSS Design Software.

Below are some Frequently Asked Questions on the general functions of the Easy RSS Design Software.

Below are some Frequently Asked Questions on the Solar Thermal Area of the Easy RSS Design Software.