# Life cycle costing analysis of deep energy retrofits of a mid-rise building to understand the impact of energy conservation measures

**Authors:** Haonan Zhang  
**arXiv:** [2304.00456](https://arxiv.org/abs/2304.00456)  
**Date:** 2023-04-02  
**Summary page:** https://www.summarizepaper.com/en/paper/2304.00456v1/

## Key points

- Building energy retrofits are crucial for achieving climate mitigation goals in Canada
- A study was conducted to understand the required capital investment, energy savings, energy cost savings, and carbon footprint for mid-rise residential buildings in Canada
- EnergyPlus software was used to evaluate pre-and post-retrofit operational energy performance of 11 retrofit measures for a typical multi-unit residential building (MURB) in Metro Vancouver, British Columbia
- Implementing these energy retrofit measures can significantly reduce GHG emissions from 27.64 tCO2e to 3.77 tCO2e for the NG-building
- Solar PV systems, air source heat pumps (ASHPs), water heater heat pumps (HPs), and HRV enhancement have great potential for achieving substantial energy savings compared to other retrofit measures
- Temperature setback control systems, lighting upgrades and airtightness enhancements present the best economic performance from a life cycle perspective
- Window replacements, ASHPs and solar PV systems are not economical choices due to their higher life cycle costs
- Although ASHPs can increase life cycle costs initially, with financial incentives provided by governments they could be the best choice to reduce GHG emissions when stakeholders make decisions on implementing energy retrofits.
- The study evaluated the cumulative effect of annual energy cost and GHG emissions for both E-building and NG-building models.
- While E-building has lower annual energy costs than NG-building after implementing retrofit measures; however, NG-building can produce significant reductions in GHG emissions.
- This study provides valuable insights into identifying key areas where mid-rise buildings can undergo retrofits to achieve significant reductions in GHG emissions while also providing economic benefits from a life cycle perspective.

## Summary

Building energy retrofits are crucial for achieving climate mitigation goals in Canada. To provide a roadmap for existing mid-rise building retrofits, a study was conducted to understand the required capital investment, energy savings, energy cost savings, and carbon footprint for mid-rise residential buildings in Canada. The study utilized EnergyPlus software to evaluate the pre-and post-retrofit operational energy performance of 11 energy retrofit measures for a typical multi-unit residential building (MURB) in Metro Vancouver, British Columbia. Two base building models powered by natural gas (NG-building) and electricity (E-building) were created using SketchUP. The results indicated that implementing these energy retrofit measures can significantly reduce GHG emissions from 27.64 tCO2e to 3.77 tCO2e for the NG-building. Solar PV systems, air source heat pumps (ASHPs), water heater heat pumps (HPs), and HRV enhancement have great potential for achieving substantial energy savings compared to other retrofit measures. Temperature setback control systems, lighting upgrades and airtightness enhancements present the best economic performance from a life cycle perspective. However, window replacements, ASHPs and solar PV systems are not economical choices due to their higher life cycle costs. Although ASHPs can increase life cycle costs for the NG-building initially, with financial incentives provided by governments they could be the best choice to reduce GHG emissions when stakeholders make decisions on implementing energy retrofits. The study also evaluated the cumulative effect of annual energy cost and GHG emissions for both E-building and NG-building models. The results showed that while E-building has lower annual energy costs than NG-building after implementing retrofit measures; however, NG-building can produce significant reductions in GHG emissions. In conclusion, this study provides valuable insights into identifying key areas where mid-rise buildings can undergo retrofits to achieve significant reductions in GHG emissions while also providing economic benefits from a life cycle perspective. These findings can help stakeholders make informed decisions about implementing sustainable retrofits in their buildings towards achieving climate mitigation goals in Canada.