In the recent years, in the Polish legislation system related to energy, environmental and construction sectors several changes have been introduced in order to support distributed generation, cogeneration and energy efficiency improvements. One of the most important schemes aimed to promote distributed generation and energy conservation is the system of certification of origin of electricity (the so called “certificate system”). A kind of a novelty in the Polish energy and environmental policy, which is quite well known from other Western countries, is the instrument which aims to increase economic efficiency, called the system of energy performance certificates (so-called “white certificates”). The value of the certificate of energy efficiency is the amount of energy saved, which is the subject of trade. Thus, companies that sell electricity, natural gas and heat to final consumers are within the system required to obtain a certain number of certificates. This amount depends on the amount of electricity sold. An entrepreneur could take a specific number of certificates in a tender announced by the President of the Energy Regulatory Office (Urząd Regulacji Energetyki). They can also buy certificates on commodity exchanges or regulated markets. Consequently, entities selling electricity, heat and gas to the final consumers are obliged to submit white certificates to the President of the Energy Regulatory Office (Urząd Regulacji Energetyki). Lack of fulfilment of this obligation results in a substitution fee of 900–2700 zł/toe. The Ministry of Economy estimates that by 2016 energy savings will have reached 2–2.5Mtoe thanks to the “white certificates system”. The costs of introducing the system of white certificates would, however, raise the price of electricity by approximately 1.5–2%. Taking into consideration that it was originally planned in 2016 to achieve energy savings of about 4.6Mtoe (now estimates give a value of about 5.78 Mtoe) and that significant potential for energy savings in the residential sector still exists, the aim of this paper is to analyse methods to improve energy efficiency in households. It is of crucial importance, that it is the least capital intensive and easiest way to achieve substantial effects in the short term. The results of the analysis carried out in this paper indicate that installations that currently have the best chance for commercial application in households and services sector are those powered by natural gas with a Stirling engine, whose work can be more tailored to the needs of the final consumer, than systems with internal combustion engine. Generated electricity covers partially the demand, and the waste heat is stored and used when needed. Lack of thermal power during periods of high demand could be covered by an auxiliary boiler, which is also fuelled by natural gas.