Sound statistics on renewable energies are important in order to ascertain energy balances at the country level, being the essential basis for market analysis, successful policy-making and evaluation. Heat production is not usually metered, but can be crudely assessed on the basis of total capacity
of the number of installed systems and an estimate of heat outputs. The availability and quality of even these crude basic statistics varies from country to country but few offer reliable information on how the significant part of primary energy used for heating is consumed. Data on heat production per system using the relevant conversion efficiencies is lacking. Bearing in mind the significant potential of REHC technologies in total primary energy use, adapting the way statistics are produced to obtain an improved data basis that allows thorough policy evaluation would be useful.
Renewable energy carriers that flow through commercial energy distribution systems can be measured and monitored. However where there is a multitude of individual installations for domestic and small industry players, heat production and consumption measurements are challenging due to the relatively high cost of metering. A data collection framework for the monitoring and reporting of the renewable energy heat and cold markets is therefore needed, though an obligation to install costly measuring equipment or procedures should not become a barrier to uptake. The IEA is currently attempting to better quantify the heating and cooling data streams by bringing additional market expertise to help develop a better estimation for the reporting of non-measured production and consumption (Francoeur, 2007).
Evaluation of the total amount of REHC in IEA countries is difficult due to the following reasons (as outlined in EU-project Therra).
1. The statistical data on heat options, especially from traditional biomass use, are poor.
2. The values used for conversion efficiencies vary by country; some use the average values found in the field from surveys, others the best values realised in the laboratory.
3. The methodology to determine the biodegradable share of MSW is not yet well defined and varies widely.
4. 
The use of ambient heat through heat pumps is not included in IEA data although a method to include it is under development.
5. Data on cooling in general and renewable energy cooling in particular (including district cooling, both free cooling and absorption) is not available.
More sophisticated and cost-effective metering instruments are needed for a national analysis of REHC measures (Furfari, 2006). The greater use of metering could also help convince consumers of the benefits that the REHC applications might have. Currently there are no low-cost methods to measure flows of heat or cold, which makes it difficult for consumers to evaluate the benefits obtained from an existing REHC application or to calculate the benefits when considering different investment options.
